Improvement of rice variety PAU 201 for aleurone colour and bacterial blight resistance using Marker Assisted Selection
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Date
2013
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Publisher
PAU
Abstract
In Punjab, Rice variety PAU 201 was released for cultivation in the year 2007. Within two years this variety occupied 25% of total area under rice because of its high yield. It gives good yield under average conditions. However, recently this variety faced problems because of red aleurone colour, susceptibility to new evolved pathotypes of bacterial blight and low amylose content. During 2010, crosses were attempted between PAU 201 and RYT 3148 to improve the characters of PAU 201 with the help of molecular markers. The F1 plants were backcrossed with recipient parent and BC 1 F 1 seeds were generated. In 2011, marker-assisted foreground selection for first gene rc7 was analyzed on 270 BC 1 F 1 plants, 97 plants showed positive result for this gene in heterozygous condition. For second target gene (Xa21), 23 plants were found to be heterozygous for Xa21 and the desirable plants were backcrossed to recurrent to generate BC2 F 1 seeds. For third gene (wx), 10 plants out of 23 were recorded for the presence of three genes (rc7, Xa21 and wx) while 13 plants had two target genes (rc7 and Xa21). BC2
F 1 seeds were sown in kharif 2012, 371 out of 669 plants were heterozygous for rc7 gene. Among 371 BC 2 F 1 plants, 231 plants were selected which looked similar to PAU 201 in terms of agro-morphological characters. Out of these, 80 plants were found positive for Xa21 and 25 plants out of 80 plants were identified to be heterozygous for RM190. So, on the basis of analysis of three genes, 25 plants were identified to the presence of the target genes. In case of two gene category, 118 plants out of 778 were selected based on morphological characters which resemble to PAU 201. During parental polymorphic survey, 69 polymorphic markers (19.8%) were identified out of 348 between parents. Four and six polymorphic markers in carrier chromosomes 7 and 11 were applied on selected plants to find out the recovery percentage of recurrent parent. The recovery percentage of selected plants varied from 50-75% in carrier chromosomes 7 and 11. Based on GGT results, some plants were observed as heterozygous condition with retain segments from the recurrent parent, while heterozygosity was observed at all loci in the remaining plants for carrier chromosomes 7 and 11. Plants (24-12-43, 24-15-5, 24-18-8, 24-18-44, 24-78-54, 24-78-58, 24-200-17,24-200-18, 24-200-19, 24-200-24, 24-200-47, 24-200-69, 24-200-70, 24-200-71 and 24-200-75) carried three target genes with recurrent parent genome to the extent of 75.0% in carrier chromosomes along with grain size and shape similar to parents
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Keywords
Red aleurone colour, Bacterial blight, Intermediate amylose content, L/B ratio, Marker assisted backcrossing method