DEVELOPMENT OF SALT TOLERANT VERSION OF KMP-149 RICE VARIETY THROUGH MARKER ASSISTED BACKCROSS BREEDING
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Date
2023-05-31
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University of Agricultural Sciences, Bangalore
Abstract
Rice is a major cereal that nourishes more than half of the global population but productivity of rice is greatly affected by soil salinity across the world which is the second most widespread abiotic stress after drought. In the present investigation 36 rice genotypes
were identified as saline tolerant following screening in 100 mM NaCl salt solution with six genotypes having new haplotype. Further, we have developed salt tolerant versions of KMP-149 through marker assisted backcross breeding by successful introgression of Saltol QTL into the genetic background of KMP-149 from the donor FL478 using Saltol QTL linked markers. While SSR markers RM8094, RM3412 and RM10748 were used in foreground selection, 77 unrelated polymorphic markers were employed for background selection. Backcrossing the F1s harboring Saltol QTL with KMP-149 as recurrent parent resulted in BC1F1 population. The foreground selection among BC1F1 plants revealed 14 triple positive plants, which were backcrossed to generate BC2F1. Background selection in plants morphologically similar to KMP-149 showed highest genome recovery of 79.87 %
and 90.26 % at BC1F1 and BC2F1 generations, respectively. Foreground selection among selected 70 BC2F2 plants identified 15 homozygous Saltol QTL positive plants with highest genome recovery of 93.51%. Similarly, in BC3F1 generation 11 plants were having Saltol QTL and had a highest genome recovery of 95.45%. In BC2F3 generation, six lines were identified as tolerant to salt stress with a visual salt injury score of 3 on screening for salinity tolerance at 100 mM NaCl concentration. BC2F2 and BC3F1 plants possessing Saltol QTL had grain and plant type comparable to that of KMP-149. Hence, improved version of KMP-149, with tolerance to salt stress, appear promising for enhancing rice production in salinity-affected soils.