Evaluation of mustard genotypes [Brassica juncea (L.) Czern and Coss] for quantitative traits and character association of seed yield and yield components at sub Himalayan region of West Bengal (India)

Brassica juncea is an important industrial and commercial oilseed crop grown primarily in India. This study aimed to assess 56 genotypes of Indian mustard to quantify genetic diversity, which aids the breeder in identifying genetically divergent parents to evaluate the proportional contributions of various components towards overall divergence. All the 56 Indian mustard genotypes were tested in RBD with three replications for 2 consecutive years i.e. 2016-17 and 2017-18 during the rabi season. Observations were recorded for 11 yield and its attributing traits. The findings revealed that height up to first branching, aphid count, penetration force and seed yield per plant had maximum PCV and GCV signifying that genetic factors have a greater impact on the inflow of these traits. Height up to first branching, secondary branches per plant, primary branches per plant, siliquae per plant, aphid count and 1000 seed weight had strong heritability combined with GA as % of mean. These indicate that the traits were controlled by additive gene action. Seed yield per plant was significantly correlated with penetration force and siliquae per plant. As a result, it's reasonable to predict that improving these traits by selection, could lead to significant yield gains. Four of the eleven PCs had eigen values greater than 1.0, accounting for 69.94% of the variance. PC I, which explained 30.31% of the overall variance. Mahalanobis D2 statistics revealed considerable genetic diversity among the genotypes. 56 genotypes were distributed into 7 clusters. This is anticipated that genotypes within a cluster are almost genetically related to one another. Cluster VII and II showed maximum inter-cluster divergence. From a breeding perspective, a divergence analysis revealed that genotypes like SKJM-05, RNWR-09-3, RW-351, B-85, DRMR-4001, RGN-386, TM52 276 and SKM-1313 can be selected as genetically divergent parents for hybridization to obtain desirable segregants

Molecular Basis of Plant Adaptation against Aridity

Environment fluctuations have become the greatest threat to global food security. Of various abiotic stress factors, aridity hampers the most yield contributing attributes. In the context of agriculture, term “aridity” refers to a protracted period of insufficient precipitation, having detrimental influence on crop development and overall biological output. A sustained drought has considerable negative effects on crops and livestock, including the reduced production, destruction of property, and livestock sell-offs. Consequently, plants themself exert various kinds of defensive mechanisms to combat the ill effects of climate change. For example, plants with small leaves, benefit from aridity as part of their strategy for modifying the soil to water shortages and nutrient restrictions. Furthermore, low genetic diversity among significant crop species, together with ecological productivity limits, must be addressed in order to adapt crops to episodic drought spells in the coming days. A deeper understanding of the molecular and genetic underpinnings of the most important intrinsic adaptation responses to drought stress seems to be beneficial for gene engineering as well as gene-based expression investigations in plant systems under hostile environment. Recently, molecular markers and “omics” have opened a huge opportunity to identify and develop specific gene constructs governing plant adaptation to environmental stress