Diversity of Agronomic Traits, Morphological Characters and Grain Quality of Traditional Rice Cultivars of Southern Thailand

Abstract

Traditional rice varieties cultivated and conserved by farmers are likely sources of germplasm for breeding new rice varieties. They possess traits potentially adaptable to a wide range of abiotic and biotic stresses. Characterization of these varieties is essential in rice breeding and provides valued information on developing new rice cultivars. This study was to characterize 135 of southern traditional rice varieties recorded agronomic traits, morphologic characters, and grain qualities composed of 24 qualitative characters and 10 quantitative characters. Using the standardized Shannon-Wiener diversity index (Hʹ), phenotypic diversity of qualitative traits indices, and gelatinization temperature (intermediate state) were invariant character (H’ = 0). Low diversity (H’ = 0.01-0.44) presents 15 characters, which six characters have dominant one state (> 80%) such as panicle exsertion (99%, well exserted), ligule feature (97%, 2 clefts). Moreover, five characters show more than one dominant states such as spikelet sterility, culm strength, leaf hair pubescence, shattering, and brown grain shape. However, quantitative characters had low diversity (Hʹ = 0.01-0.09). Pearson’s correlation analysis revealed low level of correlation coefficient (r = -0.35-0.26). Principal component analyses showed similarity of quantitative traits in southern traditional rice varieties and non-dissimilarity in 95%
confidence ellipses around their locations. Multiple correspondence analysis of medium – high Hʹ qualitative traits showed associated traits among the varieties. White and strew colored sterile lemma associated with soft to medium soft gel consistency, green leaf sheath and white, which these associated traits were commonly found in southern traditional rice varieties. Moreover, other associated traits were found. Medium gel consistency associated with green with purple line leaf sheath, brown stigma, and brown sterile lemma. Hard gel consistency associated with dark purple sterile lemma and purple apiculus.