Morpho-agronomic diversity analysis of 20 lines of thermo-sensitive genetic male sterile rice

Twenty thermo-sensitive genetic male sterile (TGMS) lines from the PhilRice-UPLB hybrid rice program were evaluated for diversity on the basis of 24 agro-morphological traits, five of which were quantitative, using the Shannon-Weaver Diversity Index. Monomorphism was observed in the lines for 8 out of 19 qualitative traits, and no significant differences were indicated for one quantitative trait. Polymorphism was observed in the lines for 11 out of 19 qualitative traits including five where more than two descriptor states were shown by the lines, namely, leaf blade color, auricle color, culm angle, ponicle exsertion, and panicle shattering; and significant differences were indicated for all quantitative traits except for culm length The mean Shannon-Weaver diversity indices were H' = 0.44 for all qualitative traits and H' = 0.66 for only those that showed polymorphism, indicating a moderate level of diversity among the 20 TGMS lines. The lack of a high degree of diversity among the lines studied indicates that more lines with more diverse ancestries should be developed to enrich the germplasm of the PhilRice-UPLB hybrid rice program to fully utilize the advantages of the TGMS system.