Studies On Thermal And Photo-response Characteristics And The Effects On Yield And Quality Formation Of Brazilian Upland Rice

To explore thermal and photo-response characteristics of Brazilian upland rice IAPAR9, the effects of light and temperature on its process and development, matter production, yield and quality formation, the experiments of pot-cultivated and different sowing time were conducted, The results were as follows:1) Heading acceleration percentage of short day, of high temperature and basic vegetative phase of IAPAR9 were 9.3%, 12.35%, 78days respectively, 10.59%, 12.64%, 76days respectively in paddy way, its thermal and photo-response type belongs to weak-weak-long. Growth duration was shortened mainly by the vegetative growth duration cut with the sowing time postponing. The correlation coefficients were significant between days of maturity and accumulated temperature, between days of maturity and days of the sowing time postponing (0.777*, -0.938** respectively).2) Leaves emerged faster with temperature increasing, but leaf number of main culm didn't decrease. LAI increased fast in the early growth stage and decreased slowly in the late growth stage. Tiller stage shortened, however earbearing tiller percent had little difference among different sowing time. The trend of dry matter yield was like a single-peak curve, the highest was the third sowing time. The highest percentage of dry matter accumulation was middle stage (from panicle initiation to full heading), early stage (from seeding to panicle initiation) secondly, late stage thirdly. The highest NAR and CGR was early stage, middle stage secondly, late stage thirdly The correlation coefficient between NAR of early stage and daily mean temperature is significant (0.789 ).3) Actual yield of the third sowing time was the highest, and the correlation coefficient between actual yield and biomass yield was significant (0.812 ). Effective tiller number and 1000 grains weight were higher in the early sowing time, mean grains per panicle were 155.4, but seed-setting percentage was only 35.03%. Because the index harvest was low and unstable,actual yield was low in different sowing time.4) The relation between the grain quality of 1APAR9 and daily mean temperature, sunshine hours during the period from heading to maturity in different sowing time showed that the correlation coefficients between brown rice, milled rice, head rice, chalky rice, chalkiness, amylose content, protein content and daily mean temperature were significant (-0.754*,-0.824*,-0.887**,0.925**,0.918**,-0.906**,-0.911**, respectively), the correlation coefficients between head rice, chalky rice, chalkiness, amylose content, protein content and sunshine hours were significant (-0.843*,0.860**,0.778*,-0.921**,-0.802*, respectively). Daily mean temperature had a greater effect on grain quality than sunshine hours.According to comprehensive analysis Brazilian upland rice was not sensitive to daylength and temperature, so it could be planted in early season or late season. The suitable sowing time was in late April in Changsha district. It could also be planted in paddy fields.