Proportion of parental line (A receptor and R pollinator) seeds improving rice hybrid production (original) (raw)
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Journal of New Seeds, 2008
Interspecific hybridization is an important technique used in improving rice populations by combining desired traits from different species. However, this could be difficult due to barriers to interspecific hybridization. The objective of this study was to determine the performance of different rice species based on seed set in an interspecific hybridization program. Five Oryza glaberrima genotypes and four interspecific inbred lines were used as female (seed) parents and two improved O. sativa and two interspecific inbred lines (NERICA 2 and NERICA 3) as male (pollen) parents to generate 36 cross combinations representing the North Carolina Design II mating scheme. Four groups of crosses were made: group A (O. glaberrima × O. sativa), group B (O. glaberrima × Interspecific), group C (Interspecific × O. sativa) and group D (Interspecific × Interspecific).
Journal of Pharmacognosy and Phytochemistry, 2020
The present experiments were conducted during Kharif 2017 & 2018 for rice hybrid seed production of PRH-10 at Sabour condition. The successful development and use of hybrid rice production technology is prerequisite to exploit its benefit across the rice growing agro climatic regions. It was reported that the production technology of hybrid seed is very much influenced by the provenance. The parental line i.e. seed parent Pusa 6A and pollen parent PRR78 significantly differ in growth duration difference based on 50 percent flowering. Application of GA3 was having significantly and positive effect on enhancing the panicle exertion alone or in combination with flag leaf clipping. For achieving maximum hybrid seed yield application of GA3 in combination with flag leaf clipping and supplementary pollination (rope pulling) is best in sabour (Bihar) condition.
Efficiency of different hybridization methods in single crosses or rice for pure line breeding
Spanish Journal of Agricultural Research, 2008
Single crosses are usually made for combining different characters from two varieties or species, at the F1 generation in a crop breeding program. Afterwards, F1 plants have to be checked out for hybridity. In rice (Oryza sativa L.), Baldi (1967) found that hand emasculation followed by pollination with anthers had a lower seed set than emasculation with water at 41-43.5°C for 5 or 8 min (which opens mature florets), followed by bagging two panicles together for pollination. This author reported varietal differences in seed set but he did not determine self-pollination rates. Water temperature should be high enough to kill pollen, but not so high as to kill ovaries. In contrast, Jennings et al. (1979), at IRRI (International Rice Research Institute, Philippines), claimed that emasculation at hot temperatures was slower and had lower seed set than hand emasculation or anther aspiration, apparently because culms were bent to introduce panicles
Breeding for Outcrossing Ability in Rice, to Enhance Seed Production for Hybrid Rice Cropping
Rice Research: Open Access, 2017
Background: Adoption of the hybrid rice varieties by farmers is often impaired by the high price of hybrid seed, due to low yields in hybrid seed production fields. Female outcrossing ability (FOA) and female hybrid seed production ability (FHSPA), defined as the rate of filled spikelets of the male sterile (MS) line and as its grain yield under outcrossing, respectively, determine plant traits for hybrid seed yield. Breeding for FOA and FHSPA in rice has suffered from the lack of a high throughput phenotyping method and the inbred breeding approach used for the development of MS lines. We developed an innovative hybrid rice breeding strategy that uses the monogenic recessive male-sterility gene ms-IR36 for the reciprocal recurrent improvement of maintainer and restorer populations. Results: High throughput screening for FOA and FHSPA can be achieved by scoring the grain weight of MS plants and the grain yield of fertile plants of progenies extracted from breeding populations segregating for the ms-IR36 gene. Using this phenotyping method in seven field trials, each involving several hundred entries, we revealed a very broad diversity for FOA (ranging from zero to 89%) and FHSPA, within the F 3 progenies of bi-parental crosses and within S 1 and S 2 progenies extracted from different breeding populations. The seven experiments produced convergent results and heritabilities of 0.59-0.90 for FHSPA and 0.45-0.72 for FOA. Correlations between FHSPA and FOA were tight and highly significant. Correlations were looser between FHSPA and grain yield of the selfed fertile sibling (GW-MF). Correlations between FOA and GW-MF were not significant. Tight significant correlation was also observed between FHSPA of S 1 lines and S 2 lines extracted from the former. Conclusion: Population breeding through recurrent selection, using the ms-IR36 gene as a tool for both recombination and seed production for testcrossing, is a favorable framework for harnessing rice genetic diversity for FHSPA. Rapid and cost-effective genetic gain for hybrid seed production can be achieved using results of the ms-IR36 gene mediated test cross seed production process as FHSPA early screening.
Determination of heterotic groups for tropical Indica hybrid rice germplasm
Theoretical and Applied Genetics, 2014
were investigated with the main objectives of (1) evaluating the magnitude of yield heterosis among marker-based parental groups, (2) examining the consistency between marker-based group and heterotic performance of hybrids, and (3) identifying foundational hybrid parents in discrete germplasm pools to provide a reference for tropical indica hybrid rice breeding. Significant differences in yield, yield heterosis and combining ability were detected among parents and among hybrids. On average, the hybrids yielded 14.8 % higher than the parents. results revealed that intergroup hybrids yielded higher, with higher yield heterosis than intra-group hybrids. Four heterotic patterns within two heterotic groups based on current IrrI Band r-line germplasm were identified. Parents in two marker-based groups were identified with limited breeding value among current IrrI hybrid rice germplasm because of their lowest contribution to heterotic hybrids. Heterotic hybrids are significantly correlated with high-yielding parents. The efficiency of breeding heterotic hybrids could be enhanced using selected parents within identified marker-based heterotic groups. This information is useful for exploiting those widely distributed IrrI hybrid rice parents.
Technological refinement to enhance profitability in hybrid rice seed production
International Journal of Chemical Studies, 2021
Rice is livelihood of majority of population in tropical and sub-tropical parts of the world. Hybrid rice varieties have been witnessed to enhance the production as well productivity over the open pollinated varieties and that’s why Indian farmers are being given preference the hybrid culture in their rice farming. If the farmers are well trained for the hybrid seed production, their income will certainly be enhanced. Keeping above facts, a series of experiments were conducted with rice hybrid NDRH2 accommodating its parental lines viz., IR58025A, IR58025B, NDR3026-3-1, along with a combination of treatments involving staggered seeding, proper application of GA3, DAP and Boric Acid, supplementary pollination, etc. measures in order to maximize the hybrid seed production. The economics of various components viz., common cost, treatment cost, cost of cultivation, gross return, net return and benefit cost (B: C) ratio of different treatments were worked out on the basis of input-output...
Flowering synchronization in hybrid rice parental lines
Australian Journal of Crop Science, 2016
The cultivation of hybrid rice is a technology that allows for an increase in grain yield of 30% relative to the grain yield of conventional cultivars. However, the main challenge for this technology is related to seed production, which has high production costs and low seed yields. Therefore, agronomic techniques that could enhance flowering synchrony of parental lines in the field are essential for an efficient production system of hybrid rice seeds. The objective of this work was to study the effects of sowing depth, plant density and fertilization with nitrogen or phosphorus as potential techniques to increase the pollen availability in the field and, consequently, the flowering synchrony between parental lines in the production of hybrid rice seeds. The experiments were conducted during two growing seasons in the Central Region of Brazil. All of the experiments were conducted as a randomized complete block in a split plot scheme; however, the experiment with P fertilization had a factorial design. Our research allow inferring that nitrogen fertilization technique applied to the soil or foliar at the time of panicle differentiation does not affect the time of onset of flowering of rice varieties INTA Puitá CL and L106R, which are potential R lines for the production of hybrid rice. Agronomic techniques of variation in sowing depth, seeding rate and the phosphate fertilization affect the time of onset of flowering from 10 to 19 degree-days, which could represent two days in the crop cycle, for the line L106R. Such techniques constitute potential alternatives for use in hybrid rice seed production systems and could be applied in alternated blocks of R lines in the field to obtain longer periods of pollen availability in the field.
The success of hybrid rice technology primarily depends on genetic purity, timely availability and the affordability of hybrid seed costs to the farmers. The production of pure hybrid seed at affordable price in rice- a self-pollinated crop, is a highly skill oriented activity. A good hybrid may not reach a large number of farmers, unless it is feasible to commercially produce the seed on large scale economically. Though there are two systems (2-line and 3- line) hybrid breeding and seed production, but at presently three line method, using cytoplasmic male sterility system, is in vogue
Journal of Plant Production
Flowering synchronization between the restorer (R) line (Giza 178) and cytoplasmic male sterile (CMS or A) line (IR58025A) in hybrid rice seed production plot is very needed to achieve greater seed yield. Twoyear experiment was carried out at the Experimental Farm of Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt in the 2020 and 2021 seasons. This study aims to examine the effect of male to female ratio (2R:10A, 2R:12A and 2R:14A), male direction (one way and two ways) and differences in days in flowering between male and female (five, two days and without differences) on productivity of hybrid rice seed. A split split-plot design in three replications was utilized. The main plots were the male to female ratio, while male direction was arranged in the sub plot sand the differences in days to flowering were located in the sub-sub plots. The obtained results showed that plant height, panicle exsertion percentage, panicle length and flag leaf angle were not significantly affected by the male to female ratio, male direction and differences in days to flowering. On the other hand, the number of panicles hill-1 , panicle weight, seed set percentage, seed yield and harvest index (%) were highly significantly affected by the male to female ratio, male direction and differences in days to flowering. The highest values of seed yield (2.432 and 2.521 t ha-1) were obtained when using the male to female ratio 2R:14A, two-way male direction and without differences in flowering.