EFFECT OF HIGH TEMPERATURE ON FLORAL CHARACTERISTICS, SEED SET AND SEED QUALITY IN PARENTAL LINES OF RICE HYBRIDS
KrishiKosh
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Title |
EFFECT OF HIGH TEMPERATURE ON FLORAL CHARACTERISTICS, SEED SET AND SEED QUALITY IN PARENTAL LINES OF RICE HYBRIDS
M.Sc. |
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Creator |
HRISHIKESH SUTRADHAR
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Contributor |
Shyamal K. Chakrabarty
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Subject |
sowing, developmental stages, rice, hybrids, fruits, planting, sowing date, yields, germinability, fertilizers
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Description |
Rice (Oryza sativa L.) is one of the world’s most important cereal, particularly in Asia, but increasingly so in Africa and Latin America as well. However, seed yields often fluctuate due to various environmental stresses. Among the abiotic stresses, heat stress is emerging as the most serious threat to hybrid rice seed production as a consequence of climate change. Global climate change is likely to increase the current vulnerability of the crop to climate, with a projected global average surface temperature increase of 1.4 – 5.8ºC by 2100. Hybrid rice with 15- 20% yield superiority over HYVs play a very important role in increasing the production of rice. More than 45 rice hybrids have been released for commercial cultivation in India. Date of flowering in the parental lines need to occur in synchrony for successful pollination and hybrid seed set. Little is known about the flowering behavior of the parental lines of Indian rice hybrids in high temperature conditions and its effect during hybrid seed production. An experiment was conducted to study the flowering pattern of parental lines of three Indian rice hybrids viz., DRRH-2 (IR 68897 A, IR68897 B, DR714-1-2 R), DRRH-3(APMS 6A, APMS 6B, RPHR-1005) , PRH-10 (PUSA 6A, PUSA 6B , PRR 78) with three different sowing dates (I: 26/03/12; II: 30/04/12 and III: 13/06/12) at the experimental field of IARI, New Delhi. The three different date of sowing i.e., I, II and III showed variation in average temperature as 32, 29.4 and 28.6 ºC respectively from nursery sowing to physiological maturity. The parental lines differed for days to booting, flowering duration, spikelet opening duration and angle, days to maturity and seed set in the A line and pollen fertility in B and R lines under different sowing dates and growing conditions. Morphological characters viz, plant height, no. of tillers, panicle length are not significantly Correlated with increasing temperature. However, high temperature increased the average number of days to booting stage (23 days), panicle emergence (22 days), 50% flowering (23 days) and days to physiological maturity (12 days) of parental line of the hybrids as compared to normal temperature, leading to wide non synchrony in flowering between the parental lines and subsequently low seed set in the female line. Pollen fertility was reduced with increasing temperature. An average yield loss (about 20%) was recorded among the parental lines of the three hybrids with 3.6ºC increase in temperature at the reproductive stage. The parental lines of DRRH 3 were found susceptible to high temperature; however, parental lines of DRRH 2 and PRH 10 showed tolerance up-to some extent against high temperature. The seed quality was assessed after harvesting. Seeds produced under high temperature showed low in vigour index I (29%), vigour index II (20%) and germination (8%) as compared to those produced under normal sowing conditions. The study identified optimum time of sowing of parental lines of the three hybrids under Delhi and similar conditions elsewhere in India for the diversification of hybrid rice seed production areas. |
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Date |
2016-03-11T17:10:48Z
2016-03-11T17:10:48Z 2013 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/65103
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Language |
en_US
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Format |
application/pdf
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Publisher |
IARI, DIVISION OF SEED SCIENCE AND TECHNOLOGY, NEW DELHI
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