Genetic and time series analysis for grain growth rate and grain filling duration under conservation agriculture in wheat (Triticum aestivum L.)

Abstract

Grain filling rate (GFR) and grain filling duration (GFD) are
most important growth traits. Therefore, the present
investigation was carried out to analyze the trend for these
traits in the mega varieties released at the different time
and to identify the type of gene action governing these
traits. The study showed continuous improvement in grain
filling rate over time and there is no indication of its
saturation and therefore, can be further explored to achieve
yield gains. Grain filling duration indicates no change in
mega varieties over time for normal sown condition largely
because of the trade-off between time and heat stress,
however, conservation agriculture condition can provide
an opportunity for its exploitation. Under late sown linear
regression showed a strong declining trend over the years.
The analysis of variance revealed the presence of significant
genetic variability, not only among the elite breeding
material specifically developed for conservation agriculture
(CA) condition but also among released varieties, indicating
sufficient scope for their exploitation. Diallel analysis of 21
F1s generated from 7 parents for GFD and GFR indicated
the preponderance of additive gene action in the material
validating the effectiveness of progeny based selection for
both traits under study. Elite breeding material CSW02
displayed high GCA for both the traits and therefore, can
be effectively involved in the crossing program to make
further gain. Cross CSW77 × CSW57 having a high value of
SCA effect for both GFR and GFD provide scope for its
exploitation through hybrid development.