A quantitative analysis to find important determinant environmental factors on seed quality of upland rice ( Oryza sativa L.)

Environmental conditions can affect seed characteristics in a variety of ways during their development and maturation. This study examined the effects of environmental factors on two aspects of seed quality, namely seed health and seed vigour. The samples were taken from five regions of rice seed production. Seed germination and seedling growth were tested to gauge seed vigour. In order to evaluate seed health, the potato dextrose agar method was used to test for seed-borne fungi contamination. According to the assessment of seed lots, changes in the environment accounted for at least 61% of variation in fungal contamination and at least 74% of variation in germination characteristics. According to stepwise regression and comparative performance analysis, the optimum amounts of minimum temperature (20.56℃), daily sunny hours (8.31), daily precipitation (0.085 mm) and daily relative humidity (79.37%) were required to achieve the best possible values for percent of normal seedling (99.39%), length of seedling (15.14 cm) and percent of germination (99.84%). The gaps between the potential values and seed production under unfavourable environmental conditions were 25.49%, 25.57 mm and 6.8% for normal seedling percentage, length of seedling and germination percentage, respectively. The results of this experiment indicate that low precipitation and relative humidity, as well as an ample supply of sunlight and high altitude in Rostam-Abad, had a significant impact on the fungi in the seeds, which resulted in better seed health and greater seed quality.