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

Grain filling rate (GFR) and grain filling duration (GFD) are most important growth traits. Therefore, the present investigation was carried out to analyze the trendfor 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 F(1)s 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 x CSW57 having a high value of SCA effect for both GFR and GFD provide scope for its exploitation through hybrid development.