This is expected to ensure the availability of new and superior varieties of irrigated rice in the near future. The selection was improved by including two treatments in the population of hybrids for selection (HPS) in the modified mass method (nitrogen fertilization 0 and 120 kg/ha). The F2 generations in the non-selection hybrid population (HPNS) consisted of 120 evaluated crosses (c), of which 42 were selected by panicle selection and identified for HPS and the pedigree nursery (PNIL).
F5 to F11 entries were in the pedigree nursery with most of the derived lines from the F5 and F6 generations. Among the 3,154 lines in PNIL under WS, 254 were identified for Advanced Observation Nursery (AON) next 2013 DS. Advanced lines with moderate response to BPH and GLH under induced method in screenhouse, 2012 DS and WS.
The same rice lines planted in the breeding farms were also assessed based on the prevalent rice diseases. Therefore, grain quality screening should be integrated into the early generation stages of variety development for transplanted irrigated ecosystem.
Development of Inbred Varieties for Direct Wet-Seeding Oliver E. Manangkil
Advanced lines produced in the development of direct wet-seeded rice varieties are further screened in ON to check whether the anaerobic germination tolerance and seedling vigor under submergence are still achieved by the plant despite the series of selection in the pedigree nursery. 82 breeding lines from ON, Preliminary Yield Trial and General Yield Trial were sown in muddy soil and covered with garden soil. A total of 93 F2 populations and 110 ON breeding lines were dry sown and immersed in seedbeds for 10 days.
In 2012, DS, 22 advanced direct wet-seeded lines and two control varieties (PSB Rc82 and Rc18) were evaluated in the PYT nursery for accommodation tolerance by determining the quantitative force resistance between breeding lines using a force meter. While in WS 48 advanced direct wet sown lines and two control varieties (PSB Rc82 and Rc18) were evaluated for accommodation resistance by determining the quantitative resistance between breeding lines using a force meter. In the GYT nursery, 30 advanced direct wet seed lines and two control varieties (PSB Rc82 and Rc18) were evaluated for accommodation tolerance by determining the quantitative force resistance between breeding lines using a force meter.
Database management through field book generation using ICIS (International Crop Information System) software was implemented in the project. For disease and pest screening, breeding lines in ON were submitted to CPD to determine response to major pests and diseases.
Development of Hybrid Rice Varieties
The information generated in this software can be stored in the local database within the institute and shared in the central database outside PhilRice such as IRRI. Retainer and restorer lines are very essential components in hybrid rice development as well. Thirty-four accessions were used to re-test the CMS lines and were included in the cross nursery to further evaluate their storage ability.
New CMS lines with stable sterility and good agronomic characters will then be declared and soon used as new testers in the source nursery. Twenty uniform carrier lines from hybrid rice breeding germplasm were used as a new parent and crossed to CMS lines to further evaluate their maintenance ability (Figure 17). The field performance of these new F1 hybrids will be evaluated at the 2013 DS in Test Cross Nursery (TCN).
Sterile plants were sterilized and planted at the Male Fertile Environment (MFE) site in Kayapa, Nueva Vizcaya for evaluation and seed propagation (Figure 19). A total of twenty promising hybrid combinations were identified in the ON and for PYT inclusion in the 2013 DS. Two heterotic two-line hybrids in the Preliminary Yield Trial (PYT) were selected for inclusion in the Multi-location Yield Trial (MYT) in the DS of 2013 for further evaluation of yield performance.
This implies the occurrence of sterility-inducing factor present in the cytoplasm or in the nucleus of both parents. Another set of improved maintenance lines is already in the pipeline which is now in the F7 and F6 generation. From these results, with appropriate CMS source and proper selection, the development of next generation CMS lines in the background of improved maintenance line with resistance gene plus good eating quality is possible.
The three-line system of hybrid breeding is a key approach to help achieve rice self-sufficiency in the country. Breeding lines from Irrigated Lowland (IL), Optimum Plant Morphology (OPM) and Tropical Japonica (TJ) breeding, were collected at the Source Nursery (SN). Field performance of generated doubled haploid lines in Test Cross Nursery (TCN), PhilRice CES, 2012.
JAAS/RS18 PR2A/RS24
Development and Improvement of Seed and Seed Production Technologies
This requires evaluation of production sites in the country to program seed production activities that will meet the seed needs of the Philippine rice farmers. The success of hybrid rice seed production depends on the quality of the seed used for planting. Identification of the best location and time of year/season optimum for seed production and quality.
During seed production of the two released TGMS hybrids, NSIC RC202H and NSIC RC204H, the S lines produced in the male fertile environment (MFE) were planted in the male sterile environment (MSE) with a mean temperature of about 27 to 35 oC. In SxP seed production, control plots are established to determine the degree of selfing of the S lines in the seed production plot. The number of seeds produced from each of BC1 and BC2 ranged from 23 to 147.
A higher level of exertion was recorded with the TGMS lines than with the CMS lines. Seed purification and multiplication of the parent lines of Mestiso 25 and Mestiso 26 took place in 2012. A five-day difference in the heading dates of the A and R lines of Mestiso 25 was noted based on the observations in 2012 WS.
The shorter difference in days to flowering and the height advantage of the R line over the A line is considered ideal for producing F1 seed. To establish F1 seed production, a ten-day sowing gap is required to synchronize the flowering of the parents. A shorter R line and a larger difference in the heading dates of the A and R lines can cause problems in achieving higher yields when producing F1 seed.
For the R-line breeder seed production, only the restorer lines of the newly released hybrids (Mestiso 21, 25 and 26) were produced. S and P foundation seed production at PhilRice Los Baños is in support of the Department of Agriculture's TGMS hybrid promotion program. Outgrowth test” is an efficient method to check the purity of the hybrid parent plants and F1 seeds.
Most of the subtypes observed in the outgrowth test of Mestiso 19 from PhilRice CMU were inbred and P-line. On the other hand, seed production activities in the wet season were done simultaneously during the evaluation of the elite inbred lines by the breeders.
