ESTIMATION OF COMBINING ABILITY AND HETEROSIS IN WHEAT

The study used a half-diallel mating fashion to identify combining ability (GCA and SCA) and heterosis of six wheat (Triticum aestivum L.) genotypes and their 15 F1 hybrids for morpho-physiological, yield, and yield-contributing traits. The present study was carried out in a randomized complete block design with three replications. The studied characters are heading days, maturity days, chlorophyll content, Plant height, Effective tillers plant-1, Total tillers plant-1, Spikes plant-1, Spike length, Filled spikelets spike-1, Unfilled spikelets spike-1, Grains spike-1, Thousand grain weight, Grain yield plant-1, Biological yield plant-1, and Harvest index Highly significant differences were observed among genotypes (parents and F1 hybrids) for all characters studied. The results also showed that the mean squares due to general (GCA) and specific (SCA) combining abilities were highly significant for all studied characters except harvest index, indicating the magnitude of both additive and non-additive gene effects in governing these traits. GCA/SCA ratios were greater than one for all characters except filled spikelets spike-1 and harvests index, indicating the dominance of additive gene effects, which play important roles in the inheritance of these characters. While the non-additive effect of the gene predominated in the inheritance of filled spikelets (spike-1) and harvests index, The parent BARI GOM-30 emerged as the best general combiner for total tillers plant-1, filled spikelets spike-1, grains spike-1, thousand-grain weight, grain yield plant-1, and harvest index. Bari Gom-28 was the best general combiner for heading days and maturity days, and Sourav was the best for effective tillers plant-1, spikes plant-1, and biological yield plant-1. The cross BARI GOM-30  SOURAV was the best specific combiner for effective tillers plant-1, total tillers plant-1, spikes plant-1, and PRODIP  SOURAV for filled spikelets spike-1. Bari GOM-33   Sourav emerged as the best specific combiner for grain yield plant-1 and Prodip    Ayt-5 for grain spike-1. Concerning heterotic effects in comparison to the midparent, the F1 hybrid BARI GOM-28  BARI GOM-33 showed maximum significant positive heterosis for chlorophyll content and biological yield plant-1 and BARI GOM-33  SOURAV for effective tillers plant-1, spikes plant-1, and grain yield plant-1. These parents and cross combinations could be used for the breeding program of wheat for potential yield. View Article DOI: 10.47856/ijaast.2022.v09i12.00

Analysis of Genetic Diversity in Some Rice Varieties and Their Performance in Bangladesh

This study was conducted to evaluate the genetic diversity for several rice features and their association with yields, as well as to identify genotypes of short-duration rice. The experiment was conducted in the field in a natural environment, and data were collected on several plant parameters for each genotype at various phases of plant development. Twenty genotypes of rice were examined based on their morphological and physiological characteristics. From July through December of 2020, the experiment was conducted at the Bangladesh Rice Research Institute's regional station in Shyampur, Rajshahi. There was significant diversity among the twenty rice genotypes for all characteristics tested. The genotype BRRI dhan57 displayed the shortest days to flowering. In terms of days to maturity, the genotype BRRI dhan57 was the earliest, with a maturity time of 107.33 days, followed by BRRI dhan56 and BRRI dhan39. The days to blooming had the highest heritability (99.75%), followed by the days to maturity (99.58%), grain yield (85.30%), thousand grain weight (85.22%), grains per panicle (84.91%), plant height (82.21%), and tillers per hill (21.61%). High heritability scores indicated that the researched qualities were less influenced by the surrounding environment. As a percentage of the mean, the genetic gain was greatest for grain yield (36.33%) and lowest for tillers per hill (6.60%) among the yield-contributing factors. In days to flowering, days to maturity, grains per panicle, and plant height, high heritability and genetic progress were seen. According to the principal component analysis (PCA), the Eigen values of the first four components of the total variance accounted for 89.46% of the total variance, indicating that these components were mostly responsible for the genetic diversity of the current materials. It was the largest cluster, containing seven rice genotypes. Clusters II and V contained five and four genotypes of rice, respectively. Clusters III and IV were the smallest, with only two genotypes apiece. The pattern of distribution of genotypes among various clusters demonstrated the significant genetic variety present in the genotypes, which may be the result of adaptation of these genotypes to certain environmental conditions. The largest value of intercluster distance indicated that cluster III genotypes were extremely distinct from cluster IV genotypes. Negative values in both vectors for tillers per hill suggested that this feature contributed the least to the total diversity. The number of panicles per hill, panicle length, weight per thousand grains, and grain yield were all positive in both directions. According to these statistics, these four characteristics contributed the most to the variety. View Article DOI: 10.47856/ijaast.2022.v09i12.00