A field experiment was conducted in alpha lattice design in subtropical region of Nepal in the wheat crop to determine the association between yield and yield attributing traits through correlation and path analysis. The result showed highly significant variations among the genotypes for all the traits under study. Simple correlation coefficients revealed that the association of grain yield with biological yield followed by harvest index, plant height, thousand grain weight and Area Under SPAD Retread Curve (AUSRC) at anthesis were positive and highly significant (at 1% level of significance). The positive and significant (at 5% level of significance) association of grains per spike followed by flag leaf area with grain yield was also found. Path analysis showed that biological yield and harvest index had the highest positive direct effect on grain yield. While other traits contribute to the grain yield significantly indirectly via biological yield and harvest index. This suggests that biological yield and harvest index having significant positive correlation and high direct effect on grain yield explained the true relationship and the direct selection of the genotypes through these traits is effective for improving yield potentiality.

A number of exotic wheat (Triticum aestivum) genotypes resistant to spot blotch caused by Cochliobolus sativus are being used to improve the resistance of commercial cultivars in the warm regions of South Asia. The objective of the present study was to determine the inheritance of field resistance to spot blotch in two resistant (R) wheat genotypes, ‘Chirya.3’ and ‘Milan/Shanghai #7’ (MS#7), which were crossed to a susceptible (S) commercial cultivar, ‘BL1473.’ The two resistant genotypes also were crossed to determine allelic relationships for resistance between them. Spot blotch severity was recorded on the parents and on F1, F2, and F3 progenies. The F1 plants from the two crosses between susceptible and resistant genotypes had low disease severity like the resistant parents, indicating that resistance in Chirya.3 and MS#7 is conditioned by dominant gene action. The F2 plants segregated in 3R:1S ratios, and the F2:3 families showed the ratio of 1R:1S:2S, segregating for R and S, suggesting that resistance in the two resistant parents is conditioned by a single, dominant gene. The F1 plants from the cross between the two resistant genotypes were resistant, whereas their F2 progenies segregated in 15R:1S, suggesting that the resistance genes in MS#7 and Chirya.3 are nonallelic. These simply inherited sources of resistance could be useful for improving spot blotch resistance in the warm regions of South Asia and also may offer useful diversity to breeding programs for developing spot-blotch-resistant wheat cultivars in other regions.

Heat stress during the flowering, pollination and grain filling periods affect maize grain yield and its attributing  traits. Twenty maize inbred lines were evaluated in alpha lattice design with two replications under heat condition during spring season from February to June, 2016 at Rampur, Chitwan, Nepal. Meterological data showed maximum mean temperature (46.2–43.28ºC) and minimum (30.52-30.77ºC) in with relative humidity 37.05 to 49.45% inside the tunnel during in April-May which coincided with the flowering, pollination and grain filling periods. The data were analyzed statistically to study the correlation and path coefficient. The analysis of variance showed that all the lines were significantly different from each other for all traits anthesis silking interval, SPAD chlorophyll and leaf senescence, tassel blast, leaf firing, plant and ear height, leaf area index, ear per plant, cob length and diameter, number of kernel ear-1, number of kernel row-1, number of kernel row, silk receptivity, shelling percentage, thousand kernel weight and grain yield. Grain yield had positive and significant phenotypic correlation with silk receptivity, shelling percentage, cob length and diameter, number of kernel ear-1, number of kernel row-1, number of kernel row, SPAD chlorophyll, thousand kernel weight and significant and negative correlation with tassel blast, anthesis silking interval, leaf area index, leaf firing. Path analysis revealed that of thousand kernel weight, shelling percentage, number of kernel ear-1 and silk receptivity exerted maximum positive direct effect on grain yield. Therefore, selection of genotypes having maximum thousand kernel weight, shellingpercentage, silk receptivity and number of kernel ear-1 and shorter anthesis silking interval, no leaf firing and tassel blast is pre-requisite for attaining improvement in grain yield under heat stress condition.

High temperature adversely affects the plant physiological processes: limits plant growth and reduction in grain yield. Heat stress is often encountered to spring sowing of maize in spring season. Twenty maize inbred lines were studied for days to 50 % anthesis and silking, anthesis-silking interval, leaf firing, tassel blast, SPAD reading and leaf senescence, plant and ear height, leaf area index, ear per plant, cob length and diameter, number of kernel/ear, number of kernel row/ear, number of kernel row, silk receptivity, shelling percentage, thousand kernel weight and grain yield in alpha lattice design at National Maize Research Program at Rampur, Chitwan,Nepal with the objective to identify superior heat stress tolerant lines. Analysis of variance showed significant difference for all the traits. Result of multivariable analysis revealed that twenty inbred lines formed four clusters. The resistance inbred lines and susceptible inbred lines formed different clusters. The members of cluster 4 were found to be tolerant to heat stress due to they had lowest value of tassel blast, leaf firing, and leaf area index with highest value of cob diameter and length, ear per plant, number of kernel row/ear, number of kernel/ear, number of kernel row, shelling percentage, silk receptivity and grain yield whereas as members of cluster 1were found most susceptible due to they had longer anthesis silking interval, with maximum tassel blast and leaf firing along with no grain yield under heat stress condition. From this study inbred lines RL-140, RML-76, RML-91 and RML-40 were found most tolerant to heat stress. These inbred lines belonging to superior cluster could be considered very useful in developing heat tolerant variety and other breeding activities.

Ninety six lentil accessions from different origins were collected from National Grain Legume Research Program, Rampur; Regional Agriculture Research Station, Nepalgunj and National Agriculture Genetic Resource Center, Khumaltar, Lalitpur. Among them; four lines were Nepal Local, forty two lines were Nepal Cross; forty seven lines were ICARDA Line and finally three lines were Indian Line. All ninety six accessions were analysed by DNA fingerprinting using thirty three selected polymorphic SSR markers. The characterization was performed in Biotechnology Unit, Nepal Agricultural Research Council, Khumaltar, Lalitpur by using standard protocols. Molecular variance analysis showed that 14 % genetic variation was found between population and 86 % genetic variation was found within population with estimated variance 0.23 between population and 1.35 within population. Highest genetic distance (9) was found between landrace ILL-7979 and RL-20. In the same way, highest Nei genetic distance (0.03) between population was shown by population 1 and population 4; and lowest genetic distance were observed within the same population accessions. The heterozygosity was probably due to the introgression of genes or duplication of microsatellite motif during the breeding and or the course of lentil line evolution. All the accessions included in this study displayed significant amount of genetic variability and genetic relatedness due to different center of origin and different genetic constitutions. The diversity detected in this study may constitute the new materials for future systematic lentil breeding programs.