Variability of upland rice genotypes response to low light intensity

Abstract

Abstract. Hairmansis A, Yullianida, Supartopo, Jamil A, Suwarno. 2017. Variability of upland rice genotypes response to low light intensity. Biodiversitas 18: 1122Biodiversitas 18: -1129. Plantation areas have a great potential to be utilized for upland rice production through intercropping. One of major constraints in the cultivation of upland rice as intercropping is low light intensity caused by shading. Improvement of rice varieties for shading tolerance is therefore important to increase rice production in upland areas. The objective of this study was to investigate the variability of upland rice genotypes responses to shading and identify the best genotypes for intercropping rice cultivation. Thirty-eight upland rice breeding lines, the shading tolerant rice variety Jatiluhur, and the shading susceptible rice variety IR64 were evaluated for their response to low light intensity in the greenhouse and the field. Greenhouse screening was conducted to determine their shading tolerance in vegetative stage while evaluation in the field was performed to evaluate their agronomic performance under 55% shading and normal conditions. Variation in upland rice genotypes on low light stress was revealed both in greenhouse and field trials. In the greenhouse trial, 12 genotypes showed higher survival rate compared to tolerant rice variety Jatiluhur. Field evaluation demonstrated that 55% shading increased plant height, reduced productive tiller number, delayed flowering time, increased spikelet sterility and reduced grain yield. Upland rice breeding line B11908F-TB-3-WN-1 showed high yield relative in shading condition compared to normal condition and had high-stress tolerance index (STI) which indicated the genotype was tolerant to shading.

Development of Shading Tolerant Rice Varieties Suitable for Intercropping Cultivation in Agroforestry Systems

“…Moreover, the productivity of upland rice in Indonesia was still very low, around 3.2 tonnes per hecta re, far below the average rice productivity in irrigated lowland which was 5.3 tonnes per hectare [8]. Rice cultivation in dry land is constrained by various problems including drought, soil acidity, low soil fertility, and blast disease caused by the fungus Pyricularia grisea [8]. In areas where rice is cultivated as intercropping in between plantation, shading become the main problem which causing yield reduction.…”

“…The presence of shading in intercropping system would disrupt photosynthetic activity, which causes inhibition of plant growth rates and reduces yields [9,10]. The shading generally causes an increase in plant height, decreases the number of productive tillers, delays flowering, decreases grain filling, increases empty grain and ultimately reduces yield of rice [11,12].…”

“…Utilization of land resources in between plantation for rice production would require shading tolerant rice varieties. However, in addition to having shading tolerance trait, the varieties for intercropping must have characteristics which are needed to a dapt to other abiotic and biotic stresses in upland such as drought, soil acidity, aluminium toxicity, phosphorous deficiency, and blast disease [8]. To obtain superior rice varieties that are adaptive to abiotic and biotic stresses in upland as intercropping system, gene sources for important traits are needed such as tolerance to various environmental stresses, having good agronomic performance and good grain quality.…”

“…The area of dry land cultivated for rice is around 1.1 million hectares per year [3]. Moreover, the productivity of upland rice in Indonesia was still very low, around 3.2 tonnes per hecta re, far below the average rice productivity in irrigated lowland which was 5.3 tonnes per hectare [8]. Rice cultivation in dry land is constrained by various problems including drought, soil acidity, low soil fertility, and blast disease caused by the fungus Pyricularia grisea [8].…”

Survival and root structure changes of rice seedlings in different cultivars under submergence condition

“…This is consistent with the report of Das et al (2009) that submergence inhibits light penetration resulting in decreased chlorophyll levels. Low light intensity in rice significantly reduces plant biomass (Hairmansis et al 2017). Decreasing of chlorophyll content during submergence is caused by ethylene that induces gene expression and enzyme activity of chlorophyllase (Sone and Sakagami 2017).…”