INTERNATIONAL JOURNAL OF AGRICULTURAL TECHNOLOGY

Volume 14, No. 07, Month DECEMBER, Year 2018, Pages 1561 - 1574

Identification of best segregating family of nsic rc222/jumbo jet under salt stress at reproductive stage for use as a mapping population

Ordonio, J. L., Vergara, G. V. and Gregorio, G. B.

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From the cross between the salt-tolerant rice landrace Jumbo Jet and the high yielding salt-sensitive variety NSIC Rc222, ten BC1F2 families were grown and evaluated for reproductive stage salt tolerance at International Rice Research Institute. Salt was applied to achieve an electrical conductivity of 6 dS/m during panicle initiation stage (60 days after sowing). Results of the salinity evaluation score showed wide variation in phenotypes among the ten BC1F2 families ranging from 3 to 8. The most saline tolerant families were T109284 (BC1F2-JJ10-P2) and T109285 (BC1F2-JJ10-P3) with salinity evaluation scores of 4 and 3, respectively, while the most sensitive to salt stress were T109286 (BC1F2-JJ10-P2), T109288 (BC1F2-JJ10-P2) and T109289 (BC1F2-JJ10-P2) scoring 8. Clear segregation pattern was observed in four families (T109282 (BC1F2-JJ04-P1), T109287 (BC1F2-JJ15-P3), T109290 (BC1F2-JJ29-P1) and T109291 (BC1F2-JJ29-P2)), showing susceptible and tolerant plants within the family. However, segregation pattern was most pronounced in T109290 (BC1F2- JJ29-P1), making it the best segregating family suited for use as a mapping population. The following traits were also evaluated at the reproductive stage: days to flowering, plant height, number of panicles, number of fertile spikelets, number of sterile spikelets, spikelet fertility, 100-grain weight and grain yield. The analysis of variance revealed significant differences between parents and among ten BC1F2 families for almost all traits except for the number of panicles and grain yield. Results also showed that among the eight parameters evaluated, grain yield was the most severely affected, and the reduction of number of fertile spikelets and spikelet fertility are the primary causes of yield loss. Based on correlation analysis, number of fertile spikelets and spikelet fertility have strong positive correlation with grain yield, hence, these traits are the most important traits contributing to grain yield of rice.

Keywords

Jumbo Jet, Mapping population, Rice, Salinity

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