Exploiting heterosis and combining ability in two-line hybrid rice

Abstract

<p>Twenty hybrids were developed from crossing four environmental genic male sterile (EGMS) lines with five testers in line × tester mating design to magnitude of heterosis over better parent for grain yield and contributing traits in rice (<em>Oryza sativa </em>L.). Five hybrids ‘WTSC9059’ × ‘Sakha101’, ‘WTSC9039’ × ‘Sakha102’, ‘WTSC9059’ × ‘Sakha108’, ‘WTSC9039’ × ‘Sakha108’ and ‘WTSC9039’ × ‘Sakha101’ express superior value for number of panicles, fertility percentage, 100-grain mass, grain yield, apparent heterosis and phenotypic acceptance. The top three heterotic combinations identified for grain yield/ha were ‘WTSC9059’ × ‘Sakha101’, ‘WTSC9039’ × ‘Sakha102’ and ‘Longping’ × ‘Sakha105’ which exhibited 100.00, 71.51 and 66.61 % heterobeltiosis, respectively. The lines ‘WTSC9059’ and ‘‘Longping’’ and testers ‘Sakha101’, ‘Sakha102’ and ‘Sakha108’ was found to be good general combiner for most of the characteristics and could be extensively used in future hybrid rice breeding program. The grain yield was correlated highly significant and positive with panicle exertion, panicle mass, fertility percentage and appearance of heterosis, otherwise the negative correlation and significant was found with flag leaf area.</p>

Evaluation of Morpho-Physiological Traits in Rice Genotypes for Adaptation under Irrigated and Water-Limited Environments

“…Even in the most productive agricultural regions, exposure to short periods of drought showed great yield losses. Growing world population and decline of water resources for crop production prioritize the development of high-yielding drought-tolerant cultivars with better adaptability to water-limited condition [7]. Drought is one of the major limitations to rice production, causing huge economic losses and having large effects on rice yield and its components, particularly during the reproductive stage [8].…”

Combining Ability and Heterotic Studies in Aromatic Rice Through Line by Tester Analysis

“…To solve this difficulty, the combining ability is used to explore the potential of certain parental lines to pass genetic information down to their offspring, which helps in selecting better parents for effective breeding (Aly, 2013;Bhati et al, 2015;Kahani et al, 2018). Among the various combining ability analysis techniques, line × tester analysis (Gaballah et al, 2021) has been frequently utilized in both self and crosspollinated crops to evaluate general and specific combing abilities of particular characteristics, as well as, to identify desirable parents and crosses (Rai et al, 2019). The general combining ability (GCA) measures the parents' average performance that demonstrates additive gene action (Sprague and Tatum, 1942).…”

Improvement ability of male parent by gibberellic acid application to enhancing the outcrossing of cytoplasmic male sterility rice lines

“…The content of endogenous gibberellic acid (GA 3 ) in male p lines with pollen abortive wild rice cytoplasm (wild abortive [WA] type male sterile [MS] line) is generally lower than that of fertile plants, therefore, resulting in spikelets unavailable for cross-pollination and producing lower seed yield (Lu, 1994;Pan et al, 2013). Exogenous application of GA 3 was done to cause the panicle base of the CMS line to emerge out of the leaf sheath (Gaballah, 2004;Gaballah et al, 2021). In addition, lower heading characteristics such as small spikelet openings, poor panicle layer carriage and poor stigma exsertion can severely reduce cross-pollination and limit seed yield production.…”