This experiment was conducted in a randomized block design with three replications at Bangladesh Agricultural Research Institute, Gazipur-1701 during the rabi season of 2010 with 25 maize inbred lines. Correlation and path coefficient analysis were done for yield and some other traits. Genotypic variations were observed for ear height and grains/row. The highest broad sense heritability (h 2 b ) was observed for yield/plant followed by ear height and 1000-grain weight. Maximum genetic advance in percentage of mean (GA) was recorded for yield/plant (92.652) and ear height (75.87). The yield/plant showed significant positive genotypic correlation (r g ) with cob diameter (0.440) and grains/row (0.265). Significant negative correlation was observed between ear height and yield and also for days to 50% tasseling. The highest direct positive effect was obtained for rows/cob. These studies suggest that cob diameter, row per cob, grains/row and ear height were the most important yield contributing factors and an attempt should, therefore, be made for an effective selection of these traits.

The study was conducted to investigate the genetic diversity of some maize inbreds under salinity stress condition using Mahalanobis’s statistic (D2) and principal component analysis. Analysis of variance showed significant difference for all the characters. Results of multivariate analysis revealed that seventeen inbred lines formed five clusters at 12 dS level of salinity. The highest intra-cluster distance was recorded in cluster IV containing three genotypes and the lowest was in cluster V having one genotype. The inter cluster D2 values revealed maximum distance among the clusters. The highest inter cluster distance was observed between clusters IV & III and lowest was between V & I. Cluster IV had the highest cluster means for cob height, tassel length, cob length, SPAD value, number of seeds/cob, 100 seed weight, cob diameter and grain yield per plant. Considering cluster distance, inter-genotypic distance, cluster mean and other agronomic performances the genotypes CZ29, CZ33 and P43 from cluster IV and E135, E158, E169, P29 and P45 from cluster III may be considered as better parents for future hybridization programs to obtain desirable segregates in respect of different yield and yield contributing characters under salinity stress. DOI: http://dx.doi.org/10.3329/bjar.v39i4.22540 Bangladesh J. Agril. Res. 39(4): 621-630, December 2014

The present study was carried out to access correlation coefficient, path analysis and genetic variability among twenty one locally developed maize hybrids for ten characters. Positive and significant genotypic, phenotypic correlation coefficient were recorded for yield with anthesis silking interval (r g = 1.00**, r p = 0.96**), cob diameter (r g = 0.99** and r p = 0.95**) and ear height (r g = 0.98** and r p = 0.94**). But days to 50% tasseling had moderate but significant positive correlation at both phenotypic and genotypic level. High genotypic coefficient of variation (GCV) was obtained from thousand seed weight, days to 50% silking, cob diameter and anthesis silking interval. The highest phenotypic coefficient of variation (PCV) was observed in thousand seed weight followed by days to 50% silking and cob diameter. The highest heritability (Hb) was observed for cob diameter (95.25) followed by days to 50% silking (94.15), days to maturity (93.85) and ear height (93.06). The characters with high GCV and higher values of heritability indicated high potential for selection. Anthesis silking interval (0.79) had the highest positive direct effect on yield followed by cob diameter (0.31), cob length (0.31) and plant height (0.04) indicating the effectiveness of direct selection. While some other characters such as days to 50% tasseling (−0.12), days to 50% silking (−1.78), ear height (−1.16), days to maturity (−0.64) exhibited indirect negative effect on yield indicating the effectiveness of indirect selection.

Forty nine CIMMYT, India Maize inbred lines were characterized based on some morphological traits and grain yield. Genetic divergences of inbred lines of maize were estimated using D2 and principal component analysis. The genotypes under study fell into five clusters. The inter cluster distance were higher than intra cluster distance suggesting wider genetic diversity among the genotypes of different groups. The maximum intra cluster value was observed in cluster IV and minimum in cluster V. The inter cluster D2 values revealed that the maximum distance among the cluster. The highest inter cluster distance was observed between cluster II & I and the lowest inter cluster distance was illustrated in cluster III & I. The cluster means were higher for days to 50% tasseling, days to 50% sillking, plant height, ear height, cob length, number of rows per cob, number of grains per row in cluster IV; cob diameter and grain yield per plant was found higher in cluster II. It is expected that crossing of inbred lines belonging high to medium D2 values tend to produce high heterosis for yield.

An experiment was conducted on Maize (Zea mays L.) to investigate the genotype × environment interaction for gain yield of maize inbreds under salinity stress. The objective of this study was to evaluate G × E interactions and yield stability in multi-environmental trials across wide ecological stress environments. Prescreened thirteen maize inbred lines collected from CYMMT, India were evaluated for phenotypic traits at different salinity conditions (8dS, 12dS and 16dS) with normal environment. The environmental mean and genotypic mean ranged from 10.3 to 49.7 g and 10.9 to 52.8 g, respectively. The regression coefficient (bi) values of these genotypes ranged from 0.44 to 1.66. Among the genotypes P43, CZ29 and CZ33 produced higher grain yield and highly responsive under different salinity level. On the other hand considering the Pi, bi, S2di and AMMI bi-plot analysis the genotypes E32, P29 and P35 showed almost stable performance across the different salinity conditions. DOI: http://dx.doi.org/10.3329/bjar.v39i2.20431 Bangladesh J. Agril. Res. 39(2): 293-301, June 2014