Maite Martínez-Eixarch and Richard H. Ellis

CROP SCIENCE, Physiology

Published in Crop Sci. 55:354–364 (2015).

https://www.crops.org/publications/cs/abstracts/55/1/354

Abstract

Extreme temperature during reproductive development affects rice (Oryza sativa L.) yield and seed quality. A controlled-environment reciprocal-transfer experiment was designed where plants from two japonica cultivars were grown at 28 and 24°C (day and night temperatures) and moved to 18 and 14°C and vice versa or from 28 and 24° to 38 and 34°C and vice versa, for 7-d periods to determine the respective temporal pattern of sensitivity of spikelet fertility, yield, and seed viability to each temperature extreme. Spikelet fertility and seed yield per panicle were severely reduced by extreme temperature in the 14-d period before anthesis; both cultivars were affected at 38 and 34°C while only Gleva was affected at 18 and 14°C. The damage was greater the earlier the panicles were stressed within this period. Later-exserted panicles compensated only partly for yield loss. Seed viability was significantly reduced by 7-d exposure to 38 and 34°C or 18 and 14°C at 1 to 7 d and 1 to 14 d after anthesis, respectively, in Gleva. Taipei 309 was not affected by 7-d exposure at 18 and 14°C; no consistent temporal pattern of sensitivity was evident at 38 and 34°C. Hence, brief exposure to low or high temperature was most damaging to spikelet fertility and yield 14 to 7 d before anthesis, coinciding with microsporogenesis; it was almost as damaging around anthesis. Seed viability was most vulnerable to low or high temperature in the 7 or 14 d after anthesis, when histodifferentiation occurs.

Figure 2. Spikelet fertility of panicles of rice plants cultivated in growth chambers during 2011 at the University of Reading, UK under

a brief (A) low- or (B) high-temperature stress or a long (c) low- or (D) high-temperature stress during reproductive development in

cultivars Gleva and Taipei 309. note that -14,-8 days after anthesis (DAA) indicates that anthesis of individual panicles exposed to

treatment occurred 14 to 8 d after treatment. c18, c28, and c38 are control treatments maintained at 18 and 14, 28 and 24, or 38 and

34°cthroughout plant growth. Observations (mean ± S.e.) are for all panicles reaching anthesis in the appropriate 7-d period (cf. Fig. 3).

Observations were not limited to the first panicle to appear on a plant: results are reported for panicles that were the first, second, and

occasionally the third to exsert within a plant. The number of fertile panicles under long-term temperature stress is shown for Taipei 309

(c, D) observations because numbers were low Many more fertile panicles were produced in Gleva (>25 in each treatment combination).