Pyramiding of major blast resistance genes into aromatic landrace Mushk Budji
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Date
2016
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SKUAST Kashmir
Abstract
Short grained aromatic rices are popular across the country and almost each State possesses a rich cultural heritage of unique quality rice types usually grown in specific ecological niches. Apart from cultivation of important high yielding varieties, considerable area is planted under aromatic landraces under certain pockets of the State. The most prominent among them are Mushk Budji and Kamad which are known for their quality and aroma, remain highly priced and enjoy huge demand in domestic markets. Mushk Budji, however, ishighly susceptible to rice blast, where losses can go as high as 70% to complete yield loss. This valuable cultivar is losing its area because of susceptibility to disease and consequently frequent crop failures. Therefore, an initiative was taken to incorporate three major genes viz., Pi54, Pi1 and Pita in the genetic background of Mushk Budji using a three-gene donor line, DHMAS70Q 164-1b. The two were crossed and BC1F1, BC2F1 and BC3F1 progenies were generated through marker-assisted backcross breeding. Marker-assisted foreground selection was carried out using molecular markers Pi54 MAS, RM224 and YL 155/87 in order to select for genes Pi54, Pi1 and Pita, respectively. In BC1F1 (Mushk Budji/DHMAS70Q164-1b//Mushk Budji), foreground selection was carried on 17 plants for the genes Pi54,Pi1 and Pita of which one plant (SKUA-485-27) was found to be heterozygous for all the three genes. The three-gene BC1F1 plant was selfed and the resulting progeny of 86 BC1F2 plants was analyzed using foreground markers. This enabled selection of nine plants that were homozygous for all the three genes. The plant SKUA-485-27 in BC1F1 was backcrossed to Mushk Budji and advanced to BC2F1. Of the 11 BC2F1 plants, SKUA-485-27-4, SKUA-485-27-7 and SKUA-485-27-R7 were found to be heterozygous for all the three genes. The BC2F2 progeny of these plants was subjected to foreground selection that helped to identify three plants homozygous for all the three genes. The backcross progenies in BC1F1, BC1F2, BC2F1, BC2F2, were subjected to background selection using 78 gene based/ SSR markers and were evaluated for agronomic traits, grain and cooking quality.Ten three-gene pyramids carrying genes Pi54+Pi1+Pita were developed during the current program. The best lines namely SKUA-485-27-4-38, SKUA-485-27-4-40, SKUA-485-27-R7-3, SKUA-485-27-77, SKUA-485-27-47 representing BC1F3 and BC2F2 generations recorded the background genome recovery ranging from 82.7 to 91.0%. The derived lines expressed resistance to diagnostic isolates under controlled conditions and also showed resistance under natural conditions of Sagam, Khudwani and Shalimar. The backcross derived lines possesses cooking quality traits and aroma similar to parent MushkBudji. The lines may be put to multi-location testing and may be released as improved resistant versions of landrace Mushk Budji.
Description
PhD Thesis submitted to SKUAST Kashmir
Keywords
Gene pyramiding, Genetics & Plant Breeding, marker assisted back cross breeding, blast resistance