Forty genotypes of greengram were studied to ascertain the genetic variability and trait association among some important morpho-physiological traits and agro-meterological indices under heat stress condition. The results indicated that both GCV and PCV estimates were high for photo thermal index, heat use efficiency and seed yield. High heritability coupled with moderate genetic advance as per cent of mean was recorded for photo-thermal unit and relative temperature depression indicated that involvement of both additive and non-additive type of gene action and possibilities of effective selection for improvement of these traits. Seed yield showed significant and positive association with days to maturity, growing degree days, relative temperature depression and heat use efficiency. Based on variability, association and path analysis; heat use efficiency, maturity, photo thermal index and growing degree days were found most contributing indices/ traits should be considered as selection criteria for discrimination of outstanding greengram genotypes under heat stress condition.

Biofortification of food crops using conventional breeding or biotechnological approach is gaining momentum to alleviate micronutrient malnutrition.  Rice is a nice choice for biofortification of grain iron and zinc content as this is a cheap and chief staple food for millions of peoples world-wide particularly the poor. In present study, generation mean analysis was done to estimate the nature and magnitude of gene effects for grain iron and zinc content in rice cross Khusisoi-RI-Sareku × IR 91175-27-1-3-1-3.  Scaling test and Joint scaling test indicated the influence of epistasis on the expression of yield, its component traits and grain Fe and Zn content and inadequacy of additive-dominance model to explain the variation in different generations. Dominance [h] gene effect was of higher magnitude as compared to additive [d] gene effect for both grain iron and grain zinc content.  Additive × additive, additive × dominance and dominance × dominance component was significant for both grain Fe and Zn content, whereas dominance × dominance component was predominant for both grain Fe and Zn content. Dominance [h] gene effect and dominance × dominance interaction acted in opposite directions, indicating duplicate type of gene action controlling the expression of both grain Fe and grain Zn content which could be a bottleneck to exploit heterosis. Heterosis breeding and recombination breeding with postponement of selection till later generations, could be effective in improving both grain Fe and grain Zn content in rice.

An investigation was carried out with forty greengram genotypes including one check Samrat during summer 2015 to find out suitable selection indices for influencing the performance of genotypes under heat stress. Seed yield showed positive and significant association with days to maturity (DM), growing degree days (GDD), relative temperature depression (RTD) and heat use efficiency (HUE). Stepwise regression analysis showed that maximum contribution was made by HUE followed by photothermal index (PTI) and DM. This indicated that HUE might be utilized as primary key factor, whereas PTI, DM and RTD might be utilized as secondary key factor for improving heat tolerance in greengram. The comparison of different functions revealed that among the single character selection index HUE (index IV) was the key component to construct selection index for terminal heat tolerance in greengram. Besidethis DM, PTI, RTD, HUE and seed yield per plant (SYP) (index XV) should be simultaneously selected to achieve maximum gain and improve the heat tolerance in greengram.

The present investigation was carried out to assess the genetic diversity by using principal component analysis for yield and yield contributing traits in thirty-two genotypes of rice under direct seeded condition (DSR). The experiment was conducted at Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar in randomized block design with three replications. The results revealed that first four component axes had eigen values 1.0, representing a cumulative variability of 76.86 %. Principal component analysis (PCA) indicate that four components (PC1 to PC4) accounted for about 76.86% of the total variation present among all the traits. Out of total principal components PC1, PC2, PC3 and PC4 with values 33.781%, 19.02%, 13.859% and 10.206% respectively, contributed more to the total variation. The first principal component had high positive loading for 15 traits out of 17. Similarly, second and third principal component had 7 traits each, fourth component with 6 traits had high positive loadings which contributed more to the diversity. Genotypes in cluster V showed higher mean performance for most of the yield attributing traits. Therefore, selection of parents for different traits would be effective from this cluster. Thus, result of the present study could be exploited in planning and execution of future breeding programme in rice under direct seeded condition.