scholarly journals Floral traits and flowering behaviors of Malaysian rice cytoplasmic male sterile and maintainer lines and its relationship with out-crossing performance

2021 ◽  
pp. 180-186
Author(s):  
Shahida Hashim ◽  
Phebe Ding ◽  
Mohd Firdaus Ismail ◽  
Asfaliza Ramli
Keyword(s):  
Seed Production ◽  
Hybrid Rice ◽  
Agricultural Research ◽  
Floral Traits ◽  
Rice Seed ◽  
Male Sterile ◽  
Floral Trait ◽  
Cytoplasmic Male Sterile ◽  
Cross Pollination ◽  
Parental Lines

Rice is a strictly self-pollinating crop. However, in hybrid rice seed production, an effective male sterility system is used to produce hybrid seed in bulk. In hybrid rice system, the pollen grains of cytoplasmic male sterile (CMS) are sterile and the female organ of the CMS depends on the fertile pollen released by the maintainer or restorer lines via out-crossing or cross-pollination in order to produce seed. Floral trait and flowering behavior of CMS and its corresponding maintainer or restorer lines are essential factors in hybrid rice seed production because they influenced the out-crossing or cross-pollination between parental lines. Two local CMSs and their corresponding maintainer lines were developed through breeding program in Malaysian Agricultural Research and Development Institute (MARDI) namely 0025A/0025B and 0047A/0047B. This study was carried out on floral traits and flowering behavior of these two hybrid line. Present studies have shown that there were variations between the CMS and its maintainer lines whether on floral trait or flowering behavior for both hybrid rice combinations. The results showed that stigma characters for both 0025A and 0047 were superior than their respective maintainers. Therefore, it is expected that the out-crossing rate would be high. Seeding date intervals need to be done on 0025A/0025B during nursery stage because the on-set of flowering between parental lines was significantly different. Panicle of both CMS was also classified as just exserted and partially-exserted and application of exogenous hormones such as gibberellic acid was useful to improve panicle elongation and consequently increase the seed set and yield. Correlation study indicates that the stigma area of both 0025A and 0047A has significant positive correlation with out-crossing rate.

scholarly journals Construction of a male sterility system for hybrid rice breeding and seed production using a nuclear male sterility gene

2016 ◽  
Vol 113 (49) ◽  
pp. 14145-14150 ◽  
Author(s):  
Zhenyi Chang ◽  
Zhufeng Chen ◽  
Na Wang ◽  
Gang Xie ◽  
Jiawei Lu ◽  
...  
Keyword(s):  
Male Sterility ◽  
Seed Production ◽  
Environmental Conditions ◽  
Hybrid Rice ◽  
Rice Breeding ◽  
Male Sterile ◽  
Red Fluorescence ◽  
Cytoplasmic Male Sterile ◽  
Cross Pollination ◽  
Self Pollination

The breeding and large-scale adoption of hybrid seeds is an important achievement in agriculture. Rice hybrid seed production uses cytoplasmic male sterile lines or photoperiod/thermo-sensitive genic male sterile lines (PTGMS) as female parent. Cytoplasmic male sterile lines are propagated via cross-pollination by corresponding maintainer lines, whereas PTGMS lines are propagated via self-pollination under environmental conditions restoring male fertility. Despite huge successes, both systems have their intrinsic drawbacks. Here, we constructed a rice male sterility system using a nuclear gene named Oryza sativa No Pollen 1 (OsNP1). OsNP1 encodes a putative glucose–methanol–choline oxidoreductase regulating tapetum degeneration and pollen exine formation; it is specifically expressed in the tapetum and miscrospores. The osnp1 mutant plant displays normal vegetative growth but complete male sterility insensitive to environmental conditions. OsNP1 was coupled with an α-amylase gene to devitalize transgenic pollen and the red fluorescence protein (DsRed) gene to mark transgenic seed and transformed into the osnp1 mutant. Self-pollination of the transgenic plant carrying a single hemizygous transgene produced nontransgenic male sterile and transgenic fertile seeds in 1:1 ratio that can be sorted out based on the red fluorescence coded by DsRed. Cross-pollination of the fertile transgenic plants to the nontransgenic male sterile plants propagated the male sterile seeds of high purity. The male sterile line was crossed with ∼1,200 individual rice germplasms available. Approximately 85% of the F1s outperformed their parents in per plant yield, and 10% out-yielded the best local cultivars, indicating that the technology is promising in hybrid rice breeding and production.

scholarly journals Combining ability, floral biology, and seed producibility of promising cytoplasmic male-sterile (CMS) lines for hybrid rice development

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Victoriano V. Casco ◽  
Rosemarie T. Tapic ◽  
Jerwin R. Undan ◽  
Anna Ma. Lourdes S. Latonio ◽  
Roel R. Suralta ◽  
...  
Keyword(s):  
Combining Ability ◽  
Hybrid Rice ◽  
Floral Biology ◽  
Outcrossing Rate ◽  
Floral Traits ◽  
Male Sterile ◽  
Ability Test ◽  
Cytoplasmic Male Sterile ◽  
Combining Abilities ◽  
Parental Lines

Abstract Background A combining ability analysis is a useful tool of plant breeders in screening and identifying promising parental lines with high potential for developing competitive rice hybrids. Also, one important factor that strongly determines the suitability of commercial utilization of hybrid rice parental lines is their extent of seed producibility. Methods In this study, the combining ability, floral biology and seed producibility of cytoplasmic male sterile (CMS) lines were investigated to identify good combiners with good seed production potential. The Line × Tester analysis was used to determine the general combining abilities (GCA) of hybrid rice parental lines, and Specific Combining Abilities (SCA) of the different hybrid combinations. A correlation analysis was also done to determine floral traits that influence the outcrossing rate of the CMS lines. There were 4 CMS lines, 6 restorer lines, 24 hybrid combinations and 1 check variety in a randomized complete block Design (RCBD) with 3 replicates. Results Results indicated that CMS lines IR79128B and IR102758B were good combiners and the most promising restorer lines were D2031-7-1-2R, Hanareumbyeo 2, and XTR036-54-10R. Based on specific combining ability test, the most promising combination was entry 10 (IR58025A/D2013-7-1-2R). It has the highest yield of 7496 kg ha−1, a high positive SCA score of 570.54, and highest standard heterosis of 12.9%. Based on floral traits, IR79128B was the most promising with a high positive GCA score of 186.93, panicle exertion rate of 74.8%, and a high outcrossing rate of 51%. There was a significant positive association between outcrossing rate, duration of floral opening, panicle exertion rate, and general combining ability. Conclusion The floral traits found to be significantly associated with outcrossing rate are useful selection criteria not only for identifying economically usable CMS lines but also for developing new and promising parental lines and hybrids. These CMS lines do not only give heterotic combinations but are also commercially producible, the two most important factors to the success of any hybrid rice breeding program.

scholarly journals Effect Of Ga3 And Row Ratio On Floral Traits Of Component Lines Of BRRI Hybrid Dhan2

2013 ◽  
Vol 38 (1) ◽  
pp. 155-163 ◽  
Author(s):  
MH Rahman ◽  
MM Khatun ◽  
MSR Khan ◽  
MM Haque ◽  
MG Rasul
Keyword(s):  
Seed Production ◽  
Hybrid Rice ◽  
Environmental Influence ◽  
Floral Traits ◽  
Rice Seed ◽  
Filament Length ◽  
Anther Length ◽  
Cms Line ◽  
Stigma Exsertion ◽  
Stigma Exsertion Rate

Component lines (A and R lines) of BRRI hybrid dhan2 were assessed under treatment of GA3 application and row ratio on days to 5% and 50% flowering, duration of opening of floret, angle of open floret, filament length, anther length, stigma length, panicle exsertion rate, stigma exsertion rate and outcrossing rate. The CMS line viz; BRRI 10A have been found to be usable female parents for hybrid rice seed production due to their stigma length, stigma exsertion rate, duration of blooming, anther length and filament length. The different between genotypic and phenotypic variation was not remarkable for most of the characters studied indicating negligible environmental influence on the traits. The maximum duration of opening of floret (158.10 min) and angle of floret opening (28.870) were obtained with the application of 350 g GA3 ha-1. The improvement in the floral traits with increased GA3 level might be due to increased availability of GA3 which enhanced floral traits. The CMS line can be used as potential female parent in hybrid rice seed production of BRRI hybrid dhan2. Bangladesh J. Agril. Res. 38(1): 155-163, March 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i1.15202

scholarly journals EVALUATION OF NEW PROMISING RICE HYBRID AND ITS PARENTAL LINES FOR FLORAL, AGRONOMIC TRAITS AND GENETIC PURITY ASSESSMENT

2019 ◽  
Vol 56 (03) ◽  
pp. 567-576
Author(s):  
Galal Anis
Keyword(s):  
Grain Quality ◽  
Seed Quality ◽  
Hybrid Rice ◽  
Agricultural Research ◽  
Floral Traits ◽  
Research Station ◽  
Genetic Purity ◽  
Cms Line ◽  
Check Variety ◽  
Parental Lines

Development of new rice hybrids with high-yielding and superior in grain quality is the most important goal to enhance food security as well as to achieve consumer requirements. High seed costs and poor grain quality are the major limiting factors for adoption of hybrid rice. A practical way to improve hybrid seed quality and to increase production is possible to increase the seed setting rate through improving the floral traits for parental lines. In the context, the study was conducted at the Rice Farm and Laboratories of Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt in consecutive three rice growing seasons in 2015, 2016 and 2017. The study focused mainly on characterization of the new promising hybrid ‘G46A/GZ9399R’ and its parental lines. The cytoplasmic male sterile (CMS) line and restorer line were evaluated for twenty-three floral traits that influence outcrossing rate in hybrid rice under two seasons and there was a marked stability for most of these traits. As compared with commercial check variety ‘Giza 178’, the new promising hybrid ‘G46A/GZ9399R’ showed its superiority in all agro-morphological traits except plant height. This hybrid was very early, adapted widely and recorded 20.19% more yield than commercial check variety ‘Giza 178’. Instead, this hybrid produced superiority in all grain quality properties except grain length was medium grain and amylose content was equal for both studied genotypes compared to the check variety. In parallel, the assessment of genetic purity established the SSR markers RM154, RM331, and RM297, amplified alleles specific to differentiate parental lines of hybrid ‘G46A/GZ9399R’.

scholarly journals Characteristics of Fertility Transition Response to the Cumulative Effective Low Temperature in a Two-Line Male Sterile Rice Cultivar

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Linxuan Wu ◽  
Huazhen Rong ◽  
Chun Chen ◽  
Xin Lin ◽  
Jiafeng Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Seed Production ◽  
Pollen Fertility ◽  
Hybrid Rice ◽  
Fertility Transition ◽  
Day Length ◽  
Sensitive Period ◽  
Rice Seed ◽  
Night Temperature ◽  
Male Sterile

Abstract Background Photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) is usually considered two-line male sterile rice because of its dual-purpose in two-line hybrid rice system: under short days and low temperatures, it is fertile and used for self-propagation, but under long days and high temperatures, it is sterile and used for hybrid seed production. Therefore, photoperiod and temperature conditions are extremely important for the fertility transition of two-line male sterile rice. In recent years, there have been frequent occurrences of abnormally low-temperature (ALT) resulting in failure of two-line hybrid rice seed production. The daily average temperature (DAT) during ALT events is sometimes higher than the critical sterility-inducing temperature (CSIT) of two-line male sterile rice, of which the night temperature is lower than the CSIT. DAT has been traditionally used as the single indicator of pollen fertility transition, but it is unknown why the fertility of two-line male sterile rice in seed production restored fertility under ALT conditions. Results For Hang93S (H93S), a newly released PTGMS line, we hypothesized fertility transition is determined mainly by the cumulative effective low temperature (ELT) and only a certain duration of low temperature is required every day during the fertility-sensitive period. This study simulated ALTs where the DAT was higher than the CSIT while some segments of night temperature were lower than the CSIT. The results showed H93S exhibited a fertility transition to varying degrees. Moreover, fertility was restored under simulated ALT conditions and pollen fertility increased with increasing cumulative ELT, indicating that the fertility transition was affected primarily by the cumulative ELT. Results also indicated that pollen fertility increased as the number of treatment days increased. Conclusions The fertility transition is caused mainly by the cumulative ELT. In two-line male sterile rice breeding, the effects of day length, ALT at night, and continuous response days should be considered together. The present study provides new insight into fertility transition so breeders can more effectively utilize the two-line male sterile rice, H93S, in breeding programs.

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