Growth responses of wild rice species to vegetative drought and rewatering
2008
Sigari, T. | Alfonso, A.A. | Roldan, D.O. | Avellanoza, E.S. | Desamero, N.V., Philippine Rice Research Inst., Munoz, Nueva Ecija (Philippines)
Improvement of rice tolerance to drought calls for exploring new genetic resources among cultivated and wild rice species. In 2007 WS, 26 wild rice varieties were evaluated in PhilRice greenhouse for vegetative drought tolerance, in RCBD with 3 replications. Four containers each represented one replicate, filled with pulverized soil, were planted to 26 wild rices and IR64. One container was kept submerged (5 cm water depth) to represent control and in the 3 others (stress) water was withheld 20 DAS for 40 days. Seedling vigor and height, leaf blade length and leaf number were measured during rice growth; entries were scored for leaf rolling and drying during drought and for recovery 5 d, 10 d, and 15 d, after re-watering. After drought and re-water the entries were harvested (40 cm line) from the base and weighed for shoot dry weight (SDW) separated in dead and green weights (SGW). Analysis of data revealed: entries were significantly different for growth characteristics, and drought and recovery responses. IR64 started to leaf roll at soil moisture content (SMC) of 13.4 percent and scored 9, 22 days after; in wild rices leaf rolling started at SMC of 10.5 percent and scored 9 within 5 days. Rate of SGW increase was 0.84 g.g-1 in IR64 and 3.2 in IRGC9138. Delayed leaf rolling and higher recovery rate in some entries may imply their higher survival under vegetative drought. Studies are needed to validate the findings and to evaluate relations between root system and function and drought and recovery responses of these entries.
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