Reference "Tagging quantitative trait loci associated with grain yield and root morphological traits in rice (Oryza sativa L.) under contrasting moisture regimes."

Reference ID

7783

Title

Tagging quantitative trait loci associated with grain yield and root morphological traits in rice (Oryza sativa L.) under contrasting moisture regimes.

Source

Euphytica, 2002, vol. 128, pp. 293-300

Authors (4)

Venuprasad-R	Shashidhar-H-E
Hittalmani-S	Hemamalini-G-S

Abstract

Plant breeding for drought-prone habitats envisages a favorable combination of
grain yield and drought resistance. Though several components enhancing drought
resistance have been identified in rice, their association with grain yield,
under low-moisture stress, has been established in very few instances. We
attempt to study the associations between rice grain yield and root system
parameters both at phenotypic and genotypic levels. The doubled haploid
population of IR64/Azucena was evaluated for root related traits at peak
vegetative stage and grain yield related traits under both low-moisture stress
and nonstress conditions. 'Mean environment' was computed for yield related
traits. Correlation and QTL mapping was attempted to find out the associations.
The correlation between maximum root length and grain yield was positive under
stress and negative in nonstress. Genotypes with thicker and deeper roots,
manifested higher biomass and grain yield under stress. Only one QTL found to
increase days to flowering in nonstress was also found to influence root volume
and dryweight negatively under stress. The study suggests that loci enhancing
grain yield and related traits were not pleiotropic with loci for desirable
root morphological traits studied under low-moisture stress at vegetative
stage, in the genetic material used in the study. It is thus possible to
combine higher grain yield and desirable root morphological traits, favorably,
to enhance productivity of rice under low-moisture stress. In rainfed
ecologies, where deep roots contribute to enhanced drought resistance in rice,
the results indicate the possibility of combining drought resistance with
higher levels of grain yield.