exploiting wild genetic diversity to broaden the genetic base for yield and stress tolerance in cultivated rice oryza sativa

Abstract

newlineThe present investigation of Exploiting wild genetic diversity to broaden the newlinegenetic base for yield and stress tolerance in cultivated rice (Oryza sativa L.) was newlineconducted in Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural newlineUniversity, Coimbatore during the period of 2017-2019. The ultimate aim of the study newlinewas to develop the prebreeding stocks for yield and stress tolerance with the newlineintrogressions from wild Oryza species which can be utilized for further breeding newlineprograms. The initial material for the study was the F3:4 population of wild rice newlinemultiparent advanced generation inter-cross (MAGIC) derived from an eight parental newlinecross involving wild and cultivated Oryza species. This population was screened for newlinethe yield, drought, blast and brown planthopper to identify the donors. newlineThe parental genotypes were having a high level of dormancy which was newlinefound to be inherited to the progenies also. So the assessment of dormancy level was newlinedone along with the standardization of a method to break it. The wild Oryza species newlinefound to have higher level of dormancy than the cultivated species which extended up newlineto 90 days after harvest. The priming treatments with different chemicals like HNO3 newlineand GA3 found to have the species dependent dormancy breaking effects. Priming newlinewith GA3 (500 ppm) showed the significantly enhanced seed quality parameters newlineirrespective of the species. So it was utilized for dormancy breaking in progenies for newlinethe further experiments. newlineSeveral positive alleles for yield attributes were reported in wild species. So, newlinethe 140 F3:4 families were screened for yield and its attributes in which a wide newlinevariation was observed in the characters were studied. The flowering time of 86 per newlinecent of the progenies was reduced with a 7 per cent reduction in the mean when newlinecompared to Asian cultivated parent. Even though there was a reduction in the mean newlinenumber of tillers and productive tillers in the population, WRM 78-2-3, WRM 78-19- newline4 and WRM 118-3-3 had more number of tillers and productive