A
recent study identified promising breeding
lines that are heat-tolerant and high-yielding after a series of field and
laboratory heat stress screening.
Titled “Screening of rice-induced mutants for heat and drought tolerance,”
the study was among the posters presented under the Plant Breeding and Genetics
category during the 23rd Federation of Crop Science Societies of the
Philippines, Inc. Scientific Conference in Clark Zone, Pampanga, 11-16 May.
Thelma Padolina, lead
researcher, said that screening promising lines that exhibit tolerance to
drought and heat stress will pave way to the development of new varieties that
addresses climate change in the country’s major rice-growing areas.
According to Ms. Padolina,
although rice normally grows at temperatures between 20 and 35°C, it is at its
most sensitive during the booting and flowering stages. Hence, even
short-duration chronic dry spells occurring during these stages will result in
substantial yield loss.
Ms. Padolina and her team
started the series of screening in 2012 where 817 mutant lines were initially
screened for drought stress and leaf blast, and later with emphasis to heat
stress.
Mutant lines are valuable
genetic variations for crop improvement. They are the results of induced
mutation where one or two of their major traits, for instance plant height and
resistance to biotic and abiotic stresses, were altered.
“In this study, we identified
promising lines from five backgrounds: 2 from traditional rice varieties
Ballatinaw and Azucena; 3 from modern varieties PSB Rc72H, PSB Rc4, and IR58;
and 1 from Nipponbare,” said Ms. Padolina.
She added that promising
lines were exposed to temperatures ranging from 21.1°C to 34.4°C at field
trials, and 34°C to 38°C at screenhouse trials for 3 consecutive seasons to
test and validate their grain fertility and pollen viability.
As of this writing, 9 mutant
lines that exhibited more than 40% grain fertility under high temperature
conditions have been identified. (PhilRice News)
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