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

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.

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

Australian Journal of Crop Science ◽

10.21475/ajcs.21.15.02.p1732 ◽

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.

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Combining ability test of parental lines for three-line hybrid rice breeding

Agriculture and Natural Resources ◽

10.34044/j.anres.2020.54.4.12 ◽

2020 ◽

Keyword(s):

Combining Ability ◽

Hybrid Rice ◽

Rice Breeding ◽

Ability Test ◽

Parental Lines

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Combining Ability and Gene Action for Yield Characteristics in Novel Aromatic Cytoplasmic Male Sterile Hybrid Rice under Water-Stress Conditions

Agriculture ◽

10.3390/agriculture11030226 ◽

2021 ◽

Vol 11 (3) ◽

pp. 226

Author(s):

Hamdi F. El-Mowafi ◽

Muneera D. F. AlKahtani ◽

Rizk M. Abdallah ◽

Amr M. Reda ◽

Kotb A. Attia ◽

...

Keyword(s):

Water Stress ◽

Combining Ability ◽

Hybrid Rice ◽

Yield Component ◽

Stress Conditions ◽

Male Sterile ◽

Genetic Components ◽

Component Traits ◽

Parental Lines ◽

Yield Component Traits

Hybrid rice parental lines with better combining abilities provide an efficient tool to increase rice production. In the current study, twenty hybrid combinations were generated from five aromatic cytoplasmic male sterile (CMS) lines and four restorer lines (three of them aromatic) using a line × tester mating design. The hybrids and their parental lines were evaluated under two water regimes: normal irrigation and water-stress. Ten yield-component traits were studied over a period of 2 years, and the significant differences between the parents and hybrids are reported in this investigation. Overall, all yield component traits were significantly affected by the water deficit and were governed by both additive and non-additive gene actions. More specifically, the grain yield (GY) was mainly controlled by non-additive gene action under both normal and water-stress conditions. The contribution of the additive variance (σ2 A) was more prominent in the genetic components of traits as compared to the dominance variance (σ2 D). The aromatic parental line CMS IR58025A and the restorer line PR2 were recorded as the best combiners for the GY and good combiners for many other characteristics under both growth conditions. The cross combinations Pusa12A/IR25571-31R and Pusa12A/Giza-Basmati-201 revealed significantly positive specific combining ability (SCA) effects for the GY under both normal and water-stress conditions. The inconsistent correlation between the general combining ability (GCA) and SCA manifested complex interactions among the positive and negative alleles of the genes controlling the yield traits. Generally, the findings of this investigation demonstrated the importance of the GCA and SCA for understanding the genetic components and gene actions of the yield characteristics in new aromatic hybrid rice parental lines. Therefore, we recommend considering these findings in the selection of elite parents for developing superior aromatic hybrid rice varieties under water-stress conditions.

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Genomic Prediction of Yield Traits in Single-Cross Hybrid Rice (Oryza sativa L.)

Frontiers in Genetics ◽

10.3389/fgene.2021.692870 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marlee R. Labroo ◽

Jauhar Ali ◽

M. Umair Aslam ◽

Erik Jon de Asis ◽

Madonna A. dela Paz ◽

...

Keyword(s):

Genetic Distance ◽

Genomic Prediction ◽

Hybrid Rice ◽

Phenotypic Selection ◽

Production Costs ◽

Breeding Cycle ◽

Male Sterile ◽

Training Set ◽

Combining Abilities ◽

Genomic Predictions

Hybrid rice varieties can outyield the best inbred varieties by 15 – 30% with appropriate management. However, hybrid rice requires more inputs and management than inbred rice to realize a yield advantage in high-yielding environments. The development of stress-tolerant hybrid rice with lowered input requirements could increase hybrid rice yield relative to production costs. We used genomic prediction to evaluate the combining abilities of 564 stress-tolerant lines used to develop Green Super Rice with 13 male sterile lines of the International Rice Research Institute for yield-related traits. We also evaluated the performance of their F1 hybrids. We identified male sterile lines with good combining ability as well as F1 hybrids with potential further use in product development. For yield per plant, accuracies of genomic predictions of hybrid genetic values ranged from 0.490 to 0.822 in cross-validation if neither parent or up to both parents were included in the training set, and both general and specific combining abilities were modeled. The accuracy of phenotypic selection for hybrid yield per plant was 0.682. The accuracy of genomic predictions of male GCA for yield per plant was 0.241, while the accuracy of phenotypic selection was 0.562. At the observed accuracies, genomic prediction of hybrid genetic value could allow improved identification of high-performing single crosses. In a reciprocal recurrent genomic selection program with an accelerated breeding cycle, observed male GCA genomic prediction accuracies would lead to similar rates of genetic gain as phenotypic selection. It is likely that prediction accuracies of male GCA could be improved further by targeted expansion of the training set. Additionally, we tested the correlation of parental genetic distance with mid-parent heterosis in the phenotyped hybrids. We found the average mid-parent heterosis for yield per plant to be consistent with existing literature values at 32.0%. In the overall population of study, parental genetic distance was significantly negatively correlated with mid-parent heterosis for yield per plant (r = −0.131) and potential yield (r = −0.092), but within female families the correlations were non-significant and near zero. As such, positive parental genetic distance was not reliably associated with positive mid-parent heterosis.

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Studies on Physio-chemical Properties of Maintainer, Restorer Lines and Hybrids of Chilies (Capsicum annuum L.)

Journal of Experimental Agriculture International ◽

10.9734/jeai/2020/v42i530526 ◽

2020 ◽

pp. 122-138

Author(s):

Maneechat Nikornpun ◽

K. Tunjai ◽

K. Kaewsombat ◽

T. Tarinta ◽

Danai Boonyakiat

Keyword(s):

Vitamin C ◽

Capsicum Annuum ◽

Combining Ability ◽

Chemical Properties ◽

General Combining Ability ◽

The Other ◽

Capsicum Annuum L ◽

Combining Abilities ◽

Parental Lines ◽

Better Than

Physio-chemical properties of hybrid chilies (Capsicum annuum L.), parental lines and commercial varieties were evaluated in three experiments and showed significant differences among them. Heterosis, and heterobeltiosis were studied in hybrids while, combining abilities were investigated in maintainers and restorers. Positive statistical differences in the general combining ability of the maintainer lines for vitamin C, capsaicin and Hue were observed and general combining ability indicated that, CA1286 and CA1303, were good maintainers for the improvement of capsaicin and vitamin C. The other maintainers;-, CA1441 and CA1442, are good for the improvement of L* and Chroma. The maintainer, CA1441, was better than CA1442 for capsaicin content,- while the maintainer, CA1442, was better than CA1441 for vitamin C. Positivity and statistically significant differences among the restorers were observed for vitamin C, capsaicin, Hue and Chroma and the lines;-, CA 1447, CA 1448, CA 1449, CA 1450 and CA 1451, were useful for the improvement of these physio-chemical properties of chilies.

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IMPROVEMENT OF GENETIC PURITY FOR THE CYTOPLASMIC MALE STERILE LINE IR58025A WITH ITS MAINTAINER OF HYBRID RICE UNDER EGYPTIAN CONDITIONS

Egyptian Journal of Agricultural Research ◽

10.21608/ejar.2017.151556 ◽

2017 ◽

Vol 95 (4) ◽

pp. 1633-1650

Author(s):

MAHMOUD A. EL SAYED

Keyword(s):

Hybrid Rice ◽

Male Sterile ◽

Male Sterile Line ◽

Genetic Purity ◽

Cytoplasmic Male Sterile

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Influence of Genetic Drift of Restoring Gene (Rf) on Seed Purity of Yuetai A, a Honglian-Type Cytoplasmic Male Sterile Line in Hybrid Rice

Rice Science ◽

10.1016/s1672-6308(08)60027-x ◽

2008 ◽

Vol 15 (2) ◽

pp. 101-109

Author(s):

Ji-feng Wang ◽

Zuo-mei Lu

Keyword(s):

Genetic Drift ◽

Hybrid Rice ◽

Male Sterile ◽

Male Sterile Line ◽

Cytoplasmic Male Sterile

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613792113 ◽

2016 ◽

Vol 113 (49) ◽

pp. 14145-14150 ◽

Cited By ~ 86

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.

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