The Indian Journal of Genetics and Plant Breeding
The Indian Society of Genetics and Plant Breeding, the oldest and most prestigious registered society of practicing Geneticists and Plant Breeders from public and private institutions and the students pursuing Genetics and Plant Breeding disciplines, has vital role to play in fostering the progress of Science of Genetics and Plant Breeding in the country.
The Indian Society of Genetics and Plant Breeding, New Delhi
Research Papers : RNASeq reveals differential regulation of genes in resistant and susceptible rice varieties during early phases of infection with Rhizoctonia solani
Sheath blight disease caused by Rhizoctonia solani is one of the most destructive diseases of the rice and causes significant yield loss worldwide. To gain insight into the transcriptome dynamics that are associated with hostpathogen interaction, comparative studies of transcriptome profiling of sheath blight resistant (Tetep) and sheath blight susceptible (HP2216) rice lines after challenge with R. solani at early stages of infection (12 dpi) were conducted. A total of 319 and 252 differentially expressed genes (DEGs) were identified in Tetep and HP2216, respectively. MapMan pathway analysis revealed expression changes within the functional groups between the two genotypes post infection with R. solani. Molecular functional enrichment analysis showed that DEGs related to the hormone metabolism, cell wall modification, respiratory burst, signalling, transcription factors and secondary metabolites were significantly upregulated in sheath blight resistant cv. Tetep. A notable difference in gene expression was observed in biotic stress metabolic pathway with majority of the genes in signalling, hormone metabolism and transcription factors getting upregulated in resistant line Tetep. In case of TFs, higher expression of WRKY at 12 dpi in Tetep supports an important role in disease resistance. This study would be helpful in identification of early induced genes and understanding molecular componentsand factors which contribute to plant disease resistance.
Copyright (c) 2017 The Indian Journal of Genetics and Plant Breeding
Genotypes x environment interactions and stability analysis of sugarcane clones (Saccharum spp.) by AMMI model in sub-tropical regions of India
Fifteen elite sugarcane clones along with five zonal standard varieties were evaluated under four production environments in the sub-tropical climate. AMMI model was employed to assess the magnitude of Genotype x environment (GE) interaction and the stability of sugarcane clones across environments. AMMI analysis revealed the significant difference among tested clones and environments. It has shown 43.17% of the variation in cane yield which could be attributed to environmental effects. The genotypic effects accounted for 45.76% variation with 11.06% of GEI effects. The early maturing high sugar varieties, Co 0238 and Co 0118 gave 89.27 t/ha and 80.11 t/ ha cane yield, respectively and thus considered as widely adapted genotypes across the environments and can be recommended for commercial cultivation in sub-tropical region. Co 98014 and Co 05011 exhibited better adaptability in ratoon trials and appeared to be suitable for multiple ratoon. Considering IPCA score, CoS 767 was most stable standard (check) across the environments. With regards to the environments, E2 (spring season plant crop) and E1 (autumn season plant crop) placed on the upper right half of perpendicular axis of AMMI biplot due to the positive interactions and hence both E2 and E1 are the favourable environments for obtaining higher cane yield.
Review article : Epigenetics : History, present status and future perspective
Epigenetics refers to the heritable changes in the pattern of gene expression resulting from the modification of DNA bases, histone proteins and/or non-coding-RNA biogenesis without altering the underlying nucleotide sequence. Genome-wide epigenetic variations are being reported which are often associated with variation in gene expression. Many of these changes occur during developmental processes and stress exposures. Both, the level of gene expression and the epigenetic changes may relapse to the pre-stress state shortly after removal of the stress. One of the common mechanisms involved in epigenetic changes is methylation of 5th carbon by the action of the enzyme DNA methyltransferase. In addition, histone proteins are post-translationally modified which may affect transcription, DNA replication, chromosome segregation/condensation, and/or DNA repair process. Small-RNA (particularly small-interfering RNAs) play a crucial role in DNA methylation via RNA-directed DNA methylation (RdDM) pathway. The epigenetic changes in plants induced by aforesaid processes can be inherited over the generations in the form of epialleles. Epigenetic change in genes caused by DNA methylation and/or histone modifications during plant development often results in phenotypic changes. It is becoming increasingly evident, that epigenetic changes have important roles to play in acclimatization, stress tolerance, adaptation, and evolution processes. With the growing reports on epigenetic changes affecting gene expression, it would be worth investigating the epigenetic machinery of gene regulation in plants, and their possible utilization in crop improvement. This review focuses on the historical development and basics of epigenetics followed by the present status and future prospects in crop improvement.
Analysis of chalcone synthase gene in chemically induced male sterility (CIMS) in wheat (Triticum aestivum L.)
Chemically induced male sterility (CIMS) is one of the male sterility system used for hybrid wheat production in China. However, the mechanism of sterility remains unclear. The expression of chalcone synthase (CHS) gene was assessed in anthers to determine its role in fertility/sterility in wheat. The expression levels of CHS gene was evaluated by realtime quantitative polymerase chain reaction (qPCR). qPCR analysis revealed that the expression levels of CHS gene were downregulated in CIMS. The sporopollenin contents in anthers underwent a sharp decrease in 1376-CIMS. Scanning electron microscopy observations revealed that pollen wall formation was significantly altered in 1376-CIMS. This phenomenon implied that CHS gene expression was inhibited during the fertility transformation process and was related to the transformation from fertility to sterility. Moreover, results indicated that CHS plays an essential role in conducting fertility in chemically interfered male sterility.
The Editor gratefully acknowledges the help rendered by following Editorial Board Members and Referees in reviewing manuscripts for the Vol. 77(1-4), 2017.
Improving pearl millet for drought tolerance – Retrospect and prospects
Drought stress is the most important production constraint of pearl millet (Pennisetum glaucum) in sub-Sahara Africa and south Asia where it is the staple diet and cheaper source of nutritious food for more than 90 million people. A much greater necessity therefore exists for improving pearl millet for drought-prone areas to attain food security in resourcelimited and fragile ecosystems. An attempt is made here to review the progress made in understanding the adaptation mechanism of pearl millet to drought situation and then to appraise how this knowledge has been used in improving drought-tolerance of pearl millet. A good amount of work has been accomplished in understanding the response of pearl millet to drought imposed at different growth stages of crop in order to understand its adaptation to drought stress. The foremost issues that have been addressed in breeding for enhanced drought tolerance in pearl millet are nature of base germplasm used, selection criterion, and representation of target environment during development, testing and evaluation of cultivars. Recent advancement in development and application of genomic tools in pearl millet is expected to improve the efficiency of breeding for improved drought tolerance. The major achievements in developing pearl millet specifically for drought conditions include identifying genetic material with built-in tolerance, developing early maturing cultivars, assigning importance to both grain and stover yields while releasing the cultivars, and identification of quantitative trait loci associated with drought tolerance. Prospects of further improvement of pearl millet for drought-prone areas are also discussed in this review.
Morphological characterization and genetic diversity analysis of interspecific hybrids of sugarcane
Interspecific hybrid derivatives involving Saccharum spontaneum, S. robustum and S. barberi were morphologically characterized with twenty two qualitative and six agronomic traits. Principal component analysis (PCA) of qualitative traits revealed that first nine principal components with eigen value > 1 accounted for a cumulative variance of 62.40 %. The traits viz., ligule shape, auricle type, internode shape and its alignment, cane thickness, dewlap color, leaf blade width and curvature, leaf sheath hairiness, bud cushion and bud groove were identified as principal discriminatory characters which will be useful in preliminary screening and identification of interspecific hybrids. Cluster analysis of qualitative traits grouped hybrids into seven clusters. Maximum inter cluster distance was between cluster IV and VI followed by cluster I and III, III and VII and between VI and VII. Metroglyph analysis of agronomic traits categorized hybrids into ten groups. Groups III, IV, V, VIII and X with highest mean index scores were identified as genetically most distant. Thirty eight superior interspecific hybrids with high index score for agronomic traits (from metroglyph analysis) and wider inter cluster distance were identified as prebreeding stocks and utilized in further backcross programmes. BC1 progenies of SBH 12-45 x Co 0303 and SRH 12-275 x Co 0240 were significantly superior for single cane weight and brix %. Elite recombinants from back crosses SSH 12-158 x Co 0209, SSH 12-409 x Co 09014 and SRH 12-119 x Co 94008 surpassed commercial check for cane yield and were on par for quality.
Introgression of sheath blight disease tolerance from the transgenic rice event Pusa Basmati1-CG27 to the variety White Ponni through backcross breeding
Sheath blight disease caused by Rhizoctonia solani is a major constraint for rice production. In order to obtain transgenic resistance against sheath blight disease, an indica rice variety Pusa Basmati1 (PB1) was transformed with constitutively express chitinase (chi11) and β-1,3- glucanase (GLU) genes. A single-copy transgenic PB1- CG27 showed a high level of tolerance to R. solani. Here, we report the introgression of sheath blight tolerance from PB1-CG27 into a non-basmati rice variety, White Ponni (WP) through backcross breeding. In each of the four backcross generations, the presence of the transgene was checked by hygromycin phosphotrans-ferase (hph) and β- glucuronidase (gus) gene-specific foreground selection markers present in the T-DNA of the PB1-CG27 event. RAPD marker-based background selection was done to choose a BC4F1 plant that was similar to the WP recurrent parent. Morphological characters of the introgressed BC4F4 plants matched those of the recurrent WP parent. RT-PCR and western blot analyses confirmed the constitutive expression of the chi11 and GLU genes in the introgressed homozygous BC4F3 plants. Bioassay with R. solani a high level disease tolerance (43 % disease reduction) revealed over the control WP plants.
Interspecific hybrid between cultivated sunflower (Helianthus annuus L.) and silver leaf sunflower H. argophyllus T. & G.: Cytomorphological and molecular characterization
Successful interspecific hybrids were obtained through hybridization between cultivated sunflower (Helianthus annuus L.; 2n=2x=34) variety ARM-243B and a wild species (H. argophyllus; 2n=2x=34) accession no. PI-468649 for transferring desirable traits like downy mildew resistance, oil content and hopper resistance from wild species into cultivated background. Morphological, cytological and simple sequence repeats (SSR)-based molecular analyses were carried out to confirm the hybrid nature of the F1 plants. The hybrids exhibited morphological features intermediate to both the parents for few attributes and showed greater similarity to wild Helianthus species for traits like leaf and stem hairiness, flower colour, stem size, branching, disc floret pigmentation, plant height, seed size and seed shape, etc. A reduction (89.9%) in pollen fertility was recorded in F1 plants. Meiotic analysis revealed the presence of univalents, bivalents, trivalents and quadrivalents in all the pollen mother cells (PMCs) analysed. Multivalents were observed in few PMCs, indicating segmental homology between chromosomes. Higher level of chromosome configurations like quadrivalents were observed in 42 out of 50 PMCs. Frequently observed chromosome configurations in diakinensis were 15 II + 1 IV and 13 II + 2 IV. The results suggested that the species H. argophyllus and H. annuus differ by 1-2 translocations. SSR primers ORS-05, ORS-896 and ORS-908 were found to reveal highly polymorphic bands in the parents.
Statistical methods for identifying traits associated with high yield potential in durum wheat under drought conditions
The knowledge of key traits contributing to stress tolerance could contribute to increasing the efficiency of the selection process leading to development of drought tolerant genotypes. Over three years (2010-13), 25 durum wheat genotypes were evaluated for different agro-physiological traits under drought conditions. Four statistical procedures including path analysis, stepwise regression, principal component analysis (PCA) and factor analysis (FA) were used to identify the most contributors to grain yield. A mean score index (MSI) based on scaling scores of selection criteria was used for genotypes characterization. The average yield productivity varied between 774 to 2360 kg/ ha across years. The statistical procedures confirmed the chlorophyll fluorescence (Fv/Fm), spike length, SPAD reading, plant height, peduncle length and heading date as the most contributors to yield productivity in durum wheat. The methodology of scoring scale provided a simple and easy visualization and identification of resilient, productive and/or contrasting genotypes according to selection criteria. The PCA and FA by justifying the high portion of variability in yield were found to be more efficient for developing proper models for indirect selection.
Short Communication: Development of a novel InDel based molecular marker, a potential to differentiate most of the traditional Basmati from non-Basmati rice varieties
Owing to the presence of desirable characteristics like extralong and slender grains, delicious taste, superior aroma and distinct flavor, Basmati rice varieties are immensely popular are fetching higher prices in the market than non Basmati rice varieties. Basmati rice is commonly adulterated with many look alike, long grain non Basmati rice varieties. Microsatellite markers (SSRs) have proven to be the markers of choice to detect Basmati adulteration. Here, we report the development of a novel InDel based STS marker, which can differentiate most of the traditional Basmati from nonBasmati rice varieties.
Evaluation of grain yield and diastatic power in barley for north western plains of India
Information on mega environments and test sites for grain yield is scanty and even not studied for diastatic power in barley and confounding G x E invariably misleads further in yield maximization and quality improvement. Average grain yield and diastatic power over the locations were exhibited as 42.3 q/ha and 101.5oL and ranged from 32.1 to 64.4 q/ha and 97.3 to 109.6oL, respectively. Initial two principal components showed reasonably good amount of the interaction component and explained nearly 60% and 57 % of the variation for grain yield for diastatic power. GGE biplots revealed that no single cultivar was winning at all the locations and indicated possibilities of crossover type genotype by environment interaction. Based on AEC abscissa and ordinate scores the genotype DWRB150 and check BH902 were observed high yielding and stable, whereas the check DWRB92 showed wider adaptability for diastatic power. For grain yield the location Hisar was classified as Type 2 ideal environment with long vector and acute angle, whereas for diastatic power the environments Ludhiana and Mathura were discriminating and representative. The study initiated possibilities to review non-informative and correlated test sites based on soil, rainfall, biotic factors and previous data to eliminate in future evaluation.
Genetic studies and identification of QTLs for sheath rot disease resistance in rice (Oryza sativa L.)
Rice genotypes BPT5204 and HP14, their direct and reciprocal F1s (DF1&RF1), F2 populations (DF2&RF2) and recombinant inbred lines (RILs) were evaluated to study the genetics of field resistance to sheath rot disease (ShR). Observed frequencies of resistant and susceptible plants in DF2 and RILs showed 27R:37S ratio and 1R:7S ratio indicating involvement of three dominant genes with complementary gene action. Significant differences between two crosses were observed between DF1&RF1, and DF2&RF2for panicle exertion and sheath rot attributing traits indicating the role of cytoplasm in manifestation of sheath rot resistance. Plants with anthocyanin pigmentation recorded significantly higher mean for panicle exertion and higher level of resistance to sheath rot disease in both F2s and RILs. Single marker analysis indicated association of anthocyanin with sheath rot resistance making purple pigmentation as probable morpholigical marker for it. Composite interval marker analysis revealed qShR-12 located on chromosome-12 and flanked by SSR markers RM7315 and RM28118 accounting 11.78% of cumulative phenotypic variation. This is the first report on genetics, role of cytoplasm, association of anthocyanin pigmentation and SSR markers with sheath rot disease resistance.
Genetic divergence studies in mungbean (Vigna radiata L. Wilczek) using morpho-physio and molecular markers to identify drought tolerant genotypes
Sixty mungbean genotypes were evaluated for genetic divergence under limited moisture condition during summer season. Based on 19 phenotypic markers, hierarchical cluster analysis identified nine clusters containing one to 15 genotypes. Principal factor analysis reduced the nineteen variables into six principal components explaining 74.66% of the total variability. Seed yield per plot, harvest index and number of seeds per pod loaded highly on the PC 1; photochemical efficiency and canopy temperature depression on PC 4 and membrane stability index, total chlorophyll content and 100 seed weight on PC 5. Genotypes MH 810, MH 721, MH 736, M 395, SML 668, Pusa 9972 were found promising with regard to yield and drought tolerance traits. Out of 31 SSR primers used, only 18 were polymorphic and amplified 74 alleles. Primer CEDG067 exhibited maximum PIC value (0.84). The NTSYS-pc UPGMA cluster analysis divided the sixty genotypes into nine distinct groups.
Rye chromosome composition and seed characters in hexaploid triticale (X Triticosecale WITTMACK)
The individual characteristic features of chromosomes in Petkus rye (diploid) and 82 hexaploid triticale accessions were assessed to identify the replaced rye chromosome pair(s) in triticale and its effect on kernel characters. GiemsaC-banding technique was used for the study. Results revealed that 24 hexaploid triticales showed full complement of rye chromosome, 34 had replacement of one pair and 24 had replacement of two pairs of rye chromosomes. Triticale strains with 2R/2D and 4R/4D substitutions had higher and medium seed set, respectively. Seed set was considerably high when both with 2R/2D and 4R/4D substitution occured together.
Development and evaluation of iso-cytoplasmic rice restorer lines for different agro-morphological traits
A set of 390 iso-cytoplasmic restorer lines were developed from 25 popular rice hybrids grown in India through pedigree breeding exercising selection for spikelet fertility, yield and extent of panicle exsertion were evaluated for various agromorphological traits. Correlation analysis showed that yield per plant was significantly correlated with number of tillers (0.208), panicle length (0.127) and spikelet fertility (0.134). Principal component analysis indicated that the first four principal components had eigenvalue of > 1.0 and cumulatively explained 74.3% of total variance. Grain characters namely, test weight (0.451), kernel length before cooking (0.418), kernel breadth before cooking (0.136) and spikelet fertility (0.402) contributed positively towards principal component I. Yield per plant showed a positively skewed distribution with panicle length and a nearly linear relationship with spikelet fertility. A core set of 21 genotypes capturing the entire range of phenotype for different traits, was identified from 390 genotypes using advanced M (maximization) strategy and statistically validated. Besides this, promising iso-cytoplasmic restorer lines originating from different hybrids were identified for various agromorphological traits. This is the first report on developing iso-cytoplasmic restorers from popular rice hybrids, which can be used in developing heterotic hybrids when crossed with diverse non-parental CMS lines.
Evaluating the expression of Hv TIP2;3 and Hv TIP4;1 in barley genotypes under different levels of salinity stress
Barley is the most salt tolerant cereal and is grown in a wide range of climatic conditions. To improve the plant tolerance to salinity‚ expression analysis of genes involved in stress tolerance could be effective in identification and development of tolerant genotypes. In this study, for evaluation of salinity effect on expression of HvTIP2;3 and HvTIP4;1 genes (encoding channel proteins in the membrane) in the root of barley, three genotypes viz., Clipper (salt susceptible), Sahara3771 (salt tolerant) and advanced breeding line (a salt tolerant line derived from a cross between Kavir and Sahara genotypes) were planted under 0, 100 and 200 mMNaCl. Analysis of variance revealed non-significant differences among genotypes, salinity levels and sampling stages for HvTIP2;3 and HvTIP4;1 genes expression pattern, whereas genotype x salinity interaction for HvTIP2;3 and genotype x sampling stage interaction were significant for both of the genes studied. The expression of HvTIP 2;3 gene in the 100 mMNaCl, was increased in salt susceptible genotype Clipper and decreased in tolerant genotypes compared with control. Mean comparison of genotype and sampling stage combination showed that the expression level of HvTIP4;1 gene 3 weeks after salinity stress was increased in Sahara and advanced breeding line and decreased in Clipper. The study revealed that these genes are affected under salinity stress‚ and their effective utilization may increase salinity tolerance in plants.
Evaluation of field pea accessions for root-knot nematode resistance and possible role of NADP dependent malic enzyme gene in host resistance
The present study was undertaken to evaluate resistance of different field pea accessions to RKN, Meloidogyne javanica under microplots and pot culture conditions. Three hundred accessions of field pea were screened initially using sick soil and evaluated after 2 months of sowing using root gall index of 1-5 scale. Based on galling index eleven accessions showing resistant reaction were further screened under controlled condition. All eleven acessions were consistent in their response to RKN infection under pot culture experiment. The partial sequence of NADPdependent malic enzyme (ME) gene was PCR amplified, sequenced and used to screen field pea accessions showing resistant and susceptible reaction against RKN using PCR amplification. PCR screening using ME specific primers showed PCR amplification only in accessions showing resistant reaction. There was no amplification of ME gene from susceptible field pea accessions. The partial sequence of putative NADP dependent Malic enzyme gene from resistant accessions of field pea has been cloned and characterized. The results indicate possible link between ME and resistance against RKN in field pea. Role of malate metabolism in generating resistance reaction against RKN is discussed.
Notification of crop varieties and registration of germplasm
Rice: Variety Ajit IET 22066 Basmati rice : Variety Pusa Basmati 1637 Basmati rice : Variety Pusa Basmati 1728 Fieldpea : Variety Central Fieldpea IPFD 12-2 (IPFD 12-2)
Dr. Dilbagh Singh Athwal Dr. Bipin C. Joshi
Selection of reliable reference genes for gene expression studies by quantitative real-time PCR in Anoectochilus roxburghii
RT-qPCR is a sensitive, efficient and reliable method for gene expression studies and reference gene expression stability was essential for RT-qPCR. Since previous studies showed that no reference gene could exhibit changeless expression pattern in all experiments, this study determined the gene expression stability of 11 reference genes across various treatments in Anoectochilus roxburghii. The results indicated that expression stability of genes varied considerably under different treatments. The genes, GAPDH, EF1α and ACT1 emerged as the most reliable reference genes.
Book Reviews Agricultural Biodiversity Heritage Sites and Systems in India; Authored by Prof. Anurudh K. Singh; Published by Asian Agri-History Foundation, 47 ICIRSAT Colony-I, Brig. Sayeed Road, Secunderabad 500 009, Telengana, India; Priced Rs. 1100. Â Field Crops-Production and Management Authored by Prof. Srinivasan Jeyaraman; Published by Oxford & IBH Publishing Co. Pvt. Ltd., New Delhi
Near-isogenic lines in NP 4 background carrying the genes Lr13, Lr18, Lr19 and Lr26 as locally adapted differentials for Indian pathotypes of wheat leaf rust
A backcross programme was conducted to transfer 13 of the Lr genes present in the leaf rust differentials being currently used in India viz., Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr10, Lr13, Lr15, Lr17a, Lr18, Lr19, Lr20 and Lr26 in the background of wheat variety NP 4 having desired agronomic traits. Homozygous resistant lines carrying these genes singly have been developed through six backcrosses and subsequent selection. Nine of these lines have already been reported. Present communication reports the remaining four lines carrying the genes Lr13, Lr18, Lr19 and Lr26. These lines being locally adapted and early maturing are easy to maintain under Indian conditions, and can be widely used for virulence analysis and genetic studies.
Efficiency of double haploid production in wheat through wide hybridization and embryo rescue
The effect of haploid induction in wheat F1s by Zea mays, Imperata cylindrica and growth environments was investigated. Doubled Haploid (DH) plant production via maize and I. cylindrica technique from field grown LWH x VL616 F1 plants was equally efficient. In second environment, four F1 hybrids viz. LWH x VL616, HPW266 x Yr15 (CN25087), HS490 x HI1563 and Local Red x WHD938 were grown in greenhouse conditions and pollinated with maize. Efficiency of DH production was considerably high from greenhouse grown F1s as compared to field grown F1s. We also report an efficient protocol for DH production in bread wheat.
Short Communication : Fertility restorer (Rf) gene linked STMS marker: An efficient tool for testing the genetic purity of hybrid rice (Oryza sativa L.) seed
A fertility restorer (Rf) gene linked STMS marker, RM 6100 as well as Grow Out Test (GOT) were used for testing the genetic purity of hybrid seed of eight popular rice hybrids. The genetic purity ranging from 96.00% to 100.00%, could be determined through marker, whereas, it varied from 97.00% to 99.50% in GOT. The comparative assessment of both methods exhibited that molecular marker was more efficient than GOT, as it could detect 0.25-2.50% more impurities very precisely as compared to GOT.It suggests that a single Rf gene linked co-dominant STMS marker appeared to be a simple, precise and quick option over GOT for testing the purity of hybrid seed lots in short span of time.
Screening of lentil (Lens culinaris Medik.) germplasm for resistance to root-knot nematode, Meloidogyne incognita
The root-knot nematode is one of the major limiting factors affecting lentil growth and yield. In the present study, 300 accessions of lentil (Lens culinaris Medik) were screened to find source of resistance to root-knot nematode, Meloidogyne incognita. Among them, nine accessions: EC223269, EC076551-C, EC267577-D, EC267555, EC255504, EC267690, IC282663, IC559890 and IC559673 were resistant, while 291 were susceptible to M. incognita. Root gall formation was reduced by 94-98% in the resistant accessions as compared to susceptible (IC560206). The nematode penetration into roots and egg-mass formation in all resistant accessions of lentil were significantly lowered compared to the susceptible accession (IC560206). Results suggest that the disease resistance in lentil accessions may be related to both post-infectional (nematode growth and development) as well as pre-infectional (penetration and establishment) defense mechanisms. Variations in nematode penetration into roots, root gall formation and egg mass formation in the resistant accessions may reflect their genetic differences related to the nematode resistance and their planting could provide a useful tool to manage root-knot nematodes in lentil crop.
Genetic analysis of recombinant inbred lines for iron deficiency chlorosis and productivity traits in groundnut
Iron deficiency is an important abiotic constraint reducing the growth and yield of groundnut especially under calcareous soils. Foliar application of Fe-chelates can overcome iron deficiency but it is not economical. Evaluation of 318 recombinant inbred lines (RILs) along with parents for iron deficiency chlorosis (IDC) and productivity traits under iron deficient soils over three years indicated significant genotypic and genotypic x environment interaction (GE) component for both IDC and productivity traits. Among the RILs, range of variation was higher than that of the parents for visual chlorotic rating (VCR), SPAD chlorophyll meter reading (SCMR) and productivity parameters across three years indicated the presence of transgressive segregants. VCR had higher phenotypic and genotypic, variances, heritability and genetic advance as per cent of mean (GAM) in all the three years as compared to SCMR. Among productivity traits, pod yield (g plant–1) had higher PCV and GCV compared to shelling per cent and 100 seed weight. Significant negative correlation between VCR and pod yield per plant indicated effect of IDC on productivity in RILs. Nine lines were superior for both IDC tolerance and productivity traits. This extensive phenotyping of RIL population for IDC tolerance under iron deficient conditions can be used for identification of genomic regions associated with IDC tolerance by genotyping of this RIL population.
Tolerance to post-emergence herbicide Imazethapyr in chickpea
The present research work aimed at identification of sources of tolerance to herbicide Imazethapyr for their possible utilization in development of herbicide tolerant chickpea. Sixty five genotypes (55 desi and 10 kabuli) screened included accessions from ICRISAT core collection, advanced breeding lines and cultivars. The herbicide tolerance score ranged from 1.9 to 5.0. Nine tolerant to moderately tolerant and three susceptible genotypes were further evaluated under control and sprayed condition. Genotype x environment interactions were observed for days to 50% flowering, NDVI, days to maturity, seed yield, biomass, harvest index, 100-seed weight and branched chain amino acids (BCAA) viz., valine, leucine and isoleucine content. Highly significant reduction in seed yield was observed in all the genotypes except ICCV 10, ICCL 82104 and ICC 1710 as revealed by pairwise comparison of means using Tukey’s test. The spraying of herbicide reduced the total biomass production. Analysis of BCAA content in sample revealed non-significant differences for percent valine content in ICCIL 04001, ICCV 00305, ICCV 96003 and ICCL 82104, for isoleucine content in all the genotypes except, ICCV 3 and ICCV 96003 and for leucine content in case of ICCV 03407, ICCIL 04001, ICCV 10, ICCV 96003, ICC 1710, ICCV 00108 and ICCL 82104. The genotypes tolerant to post-emergence herbicide Imazethapyr identified based on non-significant reduction in the yield attributes and BCAA content in the sample were ICC 82104, ICCV 10, ICCV 96003, ICC 00305 and ICC 1710. These genotypes can be used to study the genetics of herbicide tolerance in chickpea and in breeding programs for developing lines with tolerance to post-emergence herbicide Imazethapyr.
Cloning and expression analysis of a novel Glutathione S-transferase gene, MsGST, from alfalfa (Medicago sativa)
Glutathione S-transferases are important enzymes in protecting cells by scavenging reactive oxygen species induced by various stresses. In this study, a novel GST gene, MsGST (KM044312), was cloned and characterized from alfalfa. The open reading frame of MsGST contains 660bp nucleotides, encoding 219 amino acid residues. Amino acid sequence alignment indicated that the deduced MsGST protein was highly homologous to other plant tau class GST sequences. According to amino acid phylogenetic analysis, the MsGST gene was clustered into the same branch with other legume plants. Real-time quantitative PCR (qRT-PCR) revealed that the expression levels of MsGST were up-regulated in both shoots and roots under ABA treatment and various stresses, including salt, drought, cold and heat stress. The effect of nodules on MsGST gene expression indicated that the induction of MsGST expression by abiotic stress is independent of rhizobium symbiosis. In conclusion, the MsGST gene may be involved in response to different abiotic stresses in alfalfa.