Toleransi Padi Gogo terhadap Naungan

Abstract

The purpose of this experiment was to evaluate several low-irradiance (1,I) tolerant and LI-sensitive genotypes of upland rice, which differ widely in their tolerance, in order to identify their anatomical and morphophysiological adaptation to shade. Tolerant genotypes responded to low light condition by increasing height, total leaf area and showed thinner leaves and mesophylls, higher chlorophyll a and chlorophyll a/b ratio and higher stomata1 density. It is suggested that the higher chlorophyll a/b ratio was likely associated with higher shading tolerance. A better adaptation was also represented by higher tiller and productive tiller number, length of panicle, number of grain per panicle, and lower spikelet sterility. These resulted in a higher grain yield per plant. Shading treatment resulted in the decrease of total protein and Rubisco activity in both genotypes, though the tolerant plants were able to maintain relatively stable Rubisco activity. The results suggested that shading tolerance in tolerant genotypes of upland rice was mediated by higher efficiency of photosynthesis.