The center aims to implement a streamlined, efficient and successful AgBiotech R&D agenda for DA with the ultimate view of creating improved agricultural technologies, productivity and increased commercial potential value and crop activities. Determining the identity of rice cultivars is of great importance for obtaining the protection of plant varieties and breeding rights. DNA-based cultivar identification has great potential in solving varietal identity problems, as it provides a unique DNA profile that can serve as the genetic identity of the variety in question.
A ladder for each of the 20 markers was already assembled and ready for use in allelic alignment. Alignment of alleles was performed by direct comparison of the allelic array with the amplified DNA samples. Multiplied products of each selected allele and a scale made from a multiplex of these alleles at each of the 6 STR markers.
Agro-morphological traits and yield performance of selected early maturing breeding lines that outperformed the tolerant control NSIC Rc192 during dry season 2012. Overview of experimental field during DS 2012 before (A) and after (B) drought imposition at 40 days after transplanting, plots for the tolerant control PSB Rc14 (C) and a tolerant entry (D) at 33 days after the imposition of drought.
Gene Discovery and Marker Development for Agronomically Impor- tant Traits
Underwater stress is a major limiting factor in the direct-seeded rice cropping system. About half of the 40 million hectares of rain-fed lowland rice fields in South and Southeast Asia are affected by flash floods at various stages of rice growth. Rice yields could be affected because climate change may increase future stresses and may exceed the ability of existing rice cultivars to adapt to the conditions (Manigbas and Sebastian, 2007).
This is in addition to the study “mapping and expression profiling of genes associated with seedling vigor in direct wet-seeded rice system”. One of the most important properties of milled rice is the percentage of whole or unbroken rice. Introducing split resistance to high yielding varieties will improve head rice recovery of the improved line/cultivar.
Figures 6 and 7 show the position of the identified polymorphic markers on the map using GGT 2.0 software (Van Berloo, 2008). To precisely locate the putative gene(s) controlling crack resistance, a continuous survey of SSR polymorphic markers will be conducted to cover the entire rice genome. This population will be the source of the following activities: molecular mapping of fissure resistance genes; investigating the genetics of traits; and for phenotypic association. We also aimed to conduct molecular genetic studies of lpa and establish a marker system that can be used in a marker-assisted breeding approach for the development of lpa brown rice in the Philippines.
Half of the produced F1 seeds (endosperm part) were evaluated for high inorganic phosphate (HIP) while the other half (with embryo part) was kept. The remainder of the F1 generated was advanced to BC2. The two BC1F1 crosses generated using NSIC Rc226 as recurrent parents were used for double crossing to pyramid the blast resistance genes present in two BC1F1 plants (Table 7). In 2010, the identification of recombinant lines for fine mapping was completed and the transfer of the resistance QTL to modern varieties continued.
This study aimed to map the region of the resistance locus and introgressive resistance to tungra in high-yielding but disease-susceptible commercial cultivars by marker-assisted breeding to characterize the resistance to tungra derived from ARC11554 by phenotyping and genotyping and develop a large population to accurately map tungro resistance QTL. The advanced backcross lines were sent to the PhilRice MID in Midsayap, North Cotabato for field screening for resistance to tungro disease and other major pests in the area. The grain yield of the backcross lines in the NSIC Rc138 background ranged from 2.5 to 7.4 mt/ha, which was lower than that of the recurrent parent (8.8 mt/ha).
On the other hand, the grain yield of the NSIC Rc15 backcross lines ranged from 1.1 to 2.5 mt/ha, which was much lower than that of the recurrent parent (6.9 mt/ha), as shown in Table 10. Therefore there were two backcross lines in NSIC Rc138 background and all four backcross lines in NSIC Rc15 background were discarded for further evaluation in the wet season.
Marker-Assisted Line Development Dindo Agustin A. Tabanao
In addition, pedigree nursery populations and elite lines were also established in the field and tested by marker-assisted selection (MAS). Based on the genotype and field data of the elite lines, 10 lines were nominated and elevated to preliminary Multi-Environmental Test (MET 0) in 2013 DS. The F2 plants of these six populations were established in the field and genotyped for the presence of tungro resistance genes tsv1 in B015 and B017, rtv in B016, and bacterial rust resistance gene Xa23 (Figure 13B) in B019 and B020.
F1 plants, produced during the dry season by backcrossing to increase the recovery of the repetitive parental genome, were planted in the field in 2012 WS. In this study, IRBB62, the donor parent of Xa4, Xa7, and Xa21 genes for bacterial blight resistance, was crossed with maintenance and restoration parental lines. Maintenance and recovery lines Mestisa 1, Mestisa 2 and Mestisa 3 obtained by backcrossing were established in the field.
From these lines, selected improved lines were used for test crossings to evaluate their retention and recovery capacity in the 2012 WS. Original and improved CMS lines of Mestiso 1 and 3 were established in the field and crossed with their corresponding improved maintenance lines for AxB seed production and with their corresponding recovery lines for AxR seed production of improved hybrids with resistance to bacterial blight (Figure 15). Six improved Mestiso 3 hybrids with introgressed Xa7 and Xa21 from AxR seed production in 2012 DS were evaluated in a replicated yield trial with a plot size of 4 m2, shown in Table 13.
In 2012, selected plants were established in each population and selected through phenotypic acceptability. Yield performance of six improved Mestiso 3 hybrids with introduced bacterial blight resistance genes in the 2012 wet season in Science City Muñoz and Magsaysay, Davao del Sur. The yield data of the highest performing NB lines evaluated in two separate replicate yield trials are shown in Table 14.
Seven genomic selection (GWS) populations, AB F6 (double cross, cycle 0), AC F5 (intermediate AB, cycle 1), AD F3 (intermediate AC, cycle 2), GB (intermediate MB) and MD (intermediate GB ), GA (intermated MA) and PA (intermated MA), were established in the field. Grain yield performance of the most efficient NB lines (Basmati 370/. PSB Rc82) evaluated in replicate yield trials in (A) PhilRice CES and (B) PhilRice Isabela during 2012 WS. Yield performance of 14 backcross lines in NSIC Rc138 and NSIC Rc15 backgrounds in a 2012 yield replicate trial.
Yield performance of six improved Mestiso 3 hybrids with introduced genes for bacterial blight resistance during the 2012 wet season in Science City Muñoz and Magsaysay, Davao del Sur. Grain yield performance of the best NB (Basmati 370/PSB Rc82) lines evaluated in replicate yield trials in (A) PhilRice CES and (B) PhilRice Isabela during 2012 WS.
