Climate resilience response of soybean and wheat varieties with genetic fidelity testing under agroforestry system
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Date
2022-04
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G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145
Abstract
The present investigation was carried out with the objective to evaluate the varieties of soybean and wheat with respect to descriptors for genetic and biochemical parameter studies under Agroforestry system along with molecular marker analysis using RAPD and ISSR primers. For the field experiment, eight varieties each of soybean and wheat, known to produce high yields under the climatic conditions of Pantnagar were evaluated for three treatments viz. shading intensity, varieties and plant population densities under the poplar based Agroforestry system. The experiment was laid out in split split plot design during two successive seasons (2017 & 2018) at Agroforestry Research Centre, G. B. Pant University of Agriculture & Technology, Pantnagar. Pooled analysis of variance of soybean for both years (2017 and 2018) revealed highly significant interactions between all three treatments for no. of pods per plant, leaf area, 100 seed weight and seed yield per plant. Pooled analysis of variance of wheat for both years (2017 and 2018) revealed highly significant interactions for all traits except the number of productive tillers, flag leaf area and biological yield. The significant interactions suggest that the magnitude of differences between the levels of one treatment depends on the other two treatments. The mean performance of soybean varieties revealed PS 1241 to outperform the rest of the varieties in both full sun and partially shaded conditions. The mean performance of wheat varieties revealed UP 2628 to be the best yielder among all the wheat varieties while, PBW 660, UP 2785 along with UP 2628 were the best performers in partially shaded conditions.
The predominance of additive gene action for trait selection under the Agroforestry system was revealed by leaf area in soybean while, grain weight per spike, grain yield and harvest index registered high estimates of genetic parameters in wheat. Estimates of correlations and path coefficients for direct and indirect effects of various traits on seed yield in soybean revealed that harvest index, 100 seed weight, plant height and biological yield were important traits for direct selection while, the number of seeds per pod, number of nodes per plant and number of pods per plant were important traits for indirect selection. In wheat, 1000 grain weight, flag leaf area, number of grains per spike and harvest index were important traits for direct selection while, grain weight per spike, biological yield and number of productive tillers per plant play an important role in indirect selection. Analysis of variance for biochemical parameters reflected significant main plot differences for chlorophyll b and total glomalin content in soybean whereas, main plot differences were observed to be significant for only total glomalin content in wheat. Highly significant varietal differences were observed for all the biochemical parameters in soybean whereas varietal differences were found to be significant for only total glomalin content in wheat. The interactions were found to be significant in only soybean for chlorophyll a, total chlorophyll and total glomalin content. The significant interactions suggested that the magnitude of differences between the varieties depended on the main plots, and vice-versa. For biochemical traits, the treatment interactions of PS 24 in partially shaded environments registered higher observation for chlorophyll a, PS 1241 for total chlorophyll and PS 1042 for total glomalin content. In wheat, UP 2526 and UP 2785 registered significantly higher glomalin content. The molecular marker analysis to evaluate the genetic fidelity/stability of soybean plants under allelopathic stress of poplar tree litter revealed the average percentage of polymorphism as 83.38% with the PIC values of ISSR primers ranging from 0.10 (UBC-812) to 0.46
(UBC-828) and that of RAPD primers ranging from 0.13 (OPA-18) to 0.34 (OPA-16).