{'fraction_non_alphanumeric': 0.016927899686520375, 'fraction_numerical': 0.02946708463949843, 'mean_word_length': 5.162162162162162, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Study of Heterosis and Genetic Parameters for Yield and its Components Traits in Hybrid Rice (Oryza sativa L.) using line x tester mating system

Heterosis is very important phenomenon where the superior performance can appear in F 1 hybrid because increasing vigorous growth which leads to healthier and faster growing plants compared to its parents. This investigation was carried out at the experimental farm of Sakha Agricultural Research Station, Kafr El-Sheik, Egypt, during 2019 and 2020 rice growing seasons to study heterosis and simple correlation of the yield and its components traits in some hybrid rice combinations, using Line x tester design among six cytoplasmic mail sterility and four restorer genotypes. The results of heterosis over mid parents and heterosis over better parent represents that the best hybrids were PR1xIR69625A, PR78xIR68902A, PR78xIR58025A, PR78xIR69625A and PR1xIR58025A could use in breeding program to improve the grain yield dependent on its superiority in many traits. The additive variance (σ 2 A) was greater than the dominance variance (σ 2 D) for the duration and panicle weight in both seasons and head rice in 2 nd growing season. Contrarily, the dominance variance (σ 2 D) was the greatest variance for the rest traits, indicating that these traits were largely governed by non-additive genes action. Grain yield exhibited highly significant and positive correlation with total biomass in both seasons and with panicle weight in 1 st season, indicating the selection based on these two traits will be more effective to improve the grain yield.