Genetic Diversity in Ahu Rices for Drought Tolerance Using Microsatellite Markers

Rice improvement in rain-fed agroecosystems requires a reliable assessment of drought tolerance in locally adapted germ
plasm. The present investigation was designed to evaluate the genetic diversity in drought-tolerant Ahu rice (Oryza sativa
L.) cultivars of Assam, India, with SSR (simple sequence repeat) genotyping. Fifty drought-tolerant lines were screened
out among 325 germplasm lines collected. A genetic variation study using 40 SSR markers revealed distinct genetic
variation among the rice landraces, with two drought-tolerant lines, Nagina22 (N22) and APO, serving as references. The
allelic count per locus throughout the twelve chromosomes varied from 2 to 6. The allelic mean per locus was 3.30, with
an average PIC (Polymorphic Information Content) of 0.6938. The UPGMA algorithm-based dendrogram segregated the
genotypes into six distinct clusters with a high degree of genetic variation. Five rice cultivars (Dumai, Tarabali, Payjihari4,
Baismuthi, and Gerem dhan1) with robust drought tolerance tendency were further characterized by means of elevated
production of ROS scavenging enzymes, cellular osmolytes. The present study will help the breeders in parental screening
for the upcoming breeding programs of drought-tolerance.