Growth and yield performance of Cucurbita spp. transplanted at different times under poplar block plantation

Abstract

Cucurbits belong to highly diverse genera, under Cucurbitaceae family, are widespread and adaptable throughout the temperate and tropical climate. Its cultivation under agroforestry system could be an effective strategy to diversify the existing arable land use system of Indo-Gangetic plains and to enhance its productivity. With this hypothesis, the current study was aimed to determine the potential of cucurbit varieties under poplar block plantation. Three cucurbit varieties (PCK-1, PPH-1 and PAU MK-1) were evaluated with three planting times (Mid-December, Mid-January and Mid-February) under two cropping systems (sole cucurbit and poplar + cucurbit) for two years during winter season (2019-20 and 2020-21). The poplar block plantation was established in north-south direction with 8 m × 2.5 m spacing. Between two cropping systems, the least variation of PAR was observed in December (13.07 and 12.8%) due to lower LAI (0.21 and 0.24) and maximum variation in April (28 and 29%) due to higher LAI (0.83 and 0.85) during 2019-20 and 2020-21, respectively. During experimentation, age of trees was five and six years and had a mean diameter, height and crown spread of 18.6 cm, 16.35 mand 20.4 m², respectively. Due to genotypic differences, a wide fruit yield (marketable) variation was observed among the three varieties under both cropping systems (poplar and open). Variety PPH-1 was having heavier fruit weight, so it recorded significantly higher average fruit yield (37.00 and 48.78 t ha^-1), while variety PCK-1 recorded the lowest fruit yield (16.27 and 20.31 t ha^-1) under both poplar and open condition. Mid-January transplanted crop gave significantly higher yield (31.25 and 38.03 t ha^-1) than the other planting times. Hull-less seeded variety PAU MK-1 recorded the significantly higher seed yield (617 and 607 kg ha^-1) and least percentage reduction in seed yield (21.8 and 23.0) under poplar during the two years; thus, better variety for snacks and oil-seed purposes. Fruit yield reduction of 21.97 and 24.37% was recorded under poplar as compared to open during 2019-20 and 2020-21, respectively. Therefore, based on present study, it is concluded that all the three cucurbit varieties could be transplanted in mid-January under poplar-based agroforestry for vegetable and seed purposes to enhance productivity and diversification from conventional rice-wheat cropping system.