Abstract:

To study the influence of meteorological conditions in the Hetao Irrigation District on the intrinsic quality and the appearance quality of sunflower seed kernels, a staged sowing experiment was adopted. The growth period of sunflowers was recorded. The contents of substances such as linoleic acid and oleic acid in sunflower seed kernels were analyzed, and the rust spot index of sunflower seeds was statistically analyzed. Excel 2010 was used to construct a response model to analyze the key meteorological factors and sensitive periods affecting the quality of sunflowers. The results show that the climatic factors such as water vapor pressure, relative humidity, average daily temperature, sunshine duration, average daily maximum temperature, average daily minimum temperature and precipitation from flowering to maturity are closely related to the content of linoleic acid and oleic acid in sunflower kernels. The influence on linoleic acid shows a parabolic characteristic with the opening downward. The influence on oleic acid and the eating rate of palm borers shows a parabolic characteristic with an upward opening, while the effect on the incidence of seed rust spot disease shows an exponential downward trend. The content of linoleic acid shows a quadratic curve with the sowing date. The content of linoleic acid is the highest when sown from May 31^st to June 1^st. The incidence index of grain rust spot disease increases exponentially with the extension of the sowing date. The optimal sowing period that takes both into account to achieve the best results is from May 25^th to June 2^nd. A binary linear equation was established to determine the inflection point by using the temperature, daily range, vapor pressure, relative humidity, sunshine duration, hydrothermal coefficient, precipitation and linoleic acid during the flowering and ripening period. During the flowering period, precipitation, relative humidity and vapor pressure are all negatively correlated with the rust spot occurrence index of sunflowers. With the increase of water and humidity, the number of drought-loving pests (thrips) sharply decreases, and thus the rust spot index also decreases accordingly. In order to facilitate the statistics of intrinsic quality and appearance quality, the two variables were normalized. By using the small grid calculation method and with the help of the Geographic Information System (ArcGIS), the quality zoning of sunflower seeds that takes into account both internal and external aspects was carried out, providing a scientific basis for the rational layout of the Hetao Irrigation District and the adjustment of agricultural structure.

Key words: seed kernel, linoleic acid, seeds, sunflower seed rust spot, normalization processing, quality division