Shading effect on generative characters of upland red rice of Southeast Sulawesi, Indonesia

Abstract

Abstract. Upland red rice (Oryza sativa) contains anthocyanin, a phenolic compounds that can act as antioxidants and functional food for human dietary. The content of functional food on upland red rice is influenced by shading condition, but the production is also influenced by environmental condition, especially the availability of light. The study aims is to assess and analyze the effect of shade on the growth and production of upland red rice. The research was conducted using the quantitative method to obtain the optimal shading condition that can increase the rice anthocyanin content and relatively high production. The research was arranged in split plot design, with shade as main plot and the different of cultivar as sub plot with three replications. The shading treatment consist of 4 levels as follows: n1=shade level < 25 %, n2=shade level 25-50%, n3=shade level 50-75% and n4=shade level > 75%. The cultivar tested were (v1) = Labandiri, (v2) = Jangkobembe, (v3) = Ranggohitam, and (v4) = Paedara. The rice planted in between teak wood trees with different age and level of canopy. The research reveals that shades had an effect in decreasing plant production (the higher level of shade, the higher the decrease level of production), but the shades can improve the quality of red rice through the increase of anthocyanin content.

Genotypic Variation of Purple Rice in Response to Shading in Yield, Anthocyanin Content, and Gene Expression

“…Moreover, shading stress decreased the dry matter accumulation of rice plants, as well as the grain weight. Plant productivity was found to be mainly controlled by the photosynthesis rate since reduced light intensity generally reduced the amount of source [11,25]. A previous study reported that shading stress reduces the supply of photosynthetic products, thereby remarkably decreasing starch biosynthesis in grains and postponing caryopsis development [26].…”

“…This factor causes plants to adapt to survive and increases photosynthesis sources, stimulating the production of more anthocyanin in plants compared to plants grown under normal light conditions. In addition, anthocyanin is degraded if the light intensity is coupled with too high a temperature [11]. A previous report showed that anthocyanins in shoot and rice grain are sensitive to low light intensity, which suggests that anthocyanins could serve as a target compound for investigating low-light stress conditions [12].…”

“…A previous study found that shade or low light intensity can affect anthocyanin levels. For example, although shade was found to reduce the production of upland rice, the anthocyanin content increased [11].…”

“…A purple leaf color is an important morphological marker and valued as an important trait for the study of rice domestication and breeding [19]. In addition, previous research found that shade stress in plants leads to an increased amount of chlorophyll (chlorophyll a, chlorophyll b, and total chlorophyll) corresponding to the higher level of shade [11]. However, a previous study found that in purple rice varieties with purple leaves, the relative gene expression of OsPL6 led to greater anthocyanin accumulation than that in purple rice varieties with green leaves [18].…”

Variation in yield attributing traits and genetic parameters estimates of some advanced promising lines of upland rice (Oryza sativa L.) grown under shade conditions

“…About 90% of the national rice production is supplied from irrigated paddy fields which are partly conserved for various purposes outside agriculture. Several programs have been implemented to maintain rice sustainability [5] and to increase rice stock levels through increase production capacity [6][7][8][9], lowering level consumption, and consuming local food as sources of carbohydrate [4], as well as expanding planting areas. Although numerous attempts have boosted rice production [10,11] grain yields have remained stagnant [12].…”