Akram Rashad Mursi Ala Muhammad al-Mahdi Ahmad Shahin Iman Nabil Mahmud Muhammad Amal Mahmud Manzalawi

الملخص EN

Soybean seed quality as expressed by physiological, physical and chemical properties was found to be affected by planting date.

This study was conducted at Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt during 2013 and 2014 summer seasons to determine the effect of three planting dates (from mid-May to mid-June at 15-day intervals) on seed quality of fifteen soybean genotypes namely; Giza 35, Giza 83, H30 and H117 (Maturity group III), Giza 22, Crawford, Clark, H2L12, and H2L20 (Maturity group IV) and L105, L 153, L155, Toano, Holladay, DR101 (Maturity group V).

Combined data showed that delaying planting date until mid-June was significantly increased germination percentage of the produced seed for all genotypes.

Toano cv.

recorded the highest value of seed germination, followed by DR101, while Giza 35 was the lowest one followed by H30.

These differences were directly related to number of days from seed planting to maturity, so that the later-maturing cultivars might produce seed with higher quality and better germination than did earlier ones.

The high seed germination of late- planting dates and late-maturing cultivars were accompanied with increases in aging germination with weight reduction in seeds and its electrical conductivity as well as seed density.

Delaying soybean planting until mid-June was significantly decreased seed oil percentage and acidity, but increased protein content.

The low viability of soybean seed produced from early- planting dates or from early-maturing genotypes was accompanied with significant increases in acidity.

The differences in seed viability proved that the more viable soybean seeds, the higher the seed protein content, but the lower the oil and acidity.

Accordingly, the early-maturing cultivars such as Giza 83, Giza 35, Clark, Crawford, H117 should be planted in June, while, Toano, Holladay, L155, L153 and L105 could be planted over a longer period of time from the second half of May in order to produce high seed quality