Studi morfologi dan fisiologi galur padi (Oryza sativa L.)toleran kekeringan

Abstract

Rice (Oryza sativa L.) is one important source of food, since rice is the staple food of the majority of the people in Indonesia. Increased demand for rice due to the rapid population growth was not met by the slower increase of rice production in Indonesia. Increasing rice production every years, can not compensate for the basic needs population in Indonesia. In addition, an increase in atmospheric temperature is expected to greatly affect of climate global world. Such as the possibility of increasing the frequency and level of drought, this situation can affects the growth and decline in rice production. Drought is a major constrain to increase rice production and it is more prominent with the atmospheric temperature and climate change. Selection for drought tolerant lines and understanding the tolerance mechanism were needed to develop drought tolerant rice variety. A research was conducted in the green house of Cikabayan, University Farm, IPB, during May to September 2010, aimed to study the morphological and physiological aspects related to drought tolerance in rice and to identify drought tolerant lines. A split-Plot Design in a randomized complete block design was applied to a pot experiment with two factor treatments of drought stresses as the main plots and rice lines as the suplots. The drought stress treatment were no drought P1 where the standing water was maintained at 2.5 cm depth and with drought stress P2 where irrigation to 2.5 cm water depth was applied when the soil water potential reaching ≤ - 32 kPa. The line treatments including 100 rice lines obtained from the Indonesian Center for Rice Research (ICRR). Ten rice seeds were sowed on the pots filled with soil media up to 4 cm below the top pot surface. Three healthy and uniform seedlings were maintained in each pots by discarding the others at 3 weeks after sowing. Fertilizers; Urea, TSP, and KCL, were applied rating (2.5 g/pot, respectively). Analysis for prolin and relative water content (RWC) in leaf were done in Molecular marker and Spectrophotometry UV-VIS laboratory, IPB. Analysis chlorophyll content and stomatal density in Micro technique laboratory, IPB. The results of this study indicated that in drought stress treatment, drought tolerant lines exhibit morphological characteristics of broader leaves, more tillers, shorter canopies, and heavier dry canopy weights; and physiological characteristics of higher relative water content (RWC) of leaves as well as higher content of prolin and chlorophyll b. Eighteen drought tolerant lines were identified based on less dry weight reduction by the drought treatment among which B11599D-TB-2-24, B11629C-MR-1-2-1, B11598C-TB-4-1-1 were the most tolerant.