EFFECT OF SOME CULTURAL PRACTICES ON GROWTH, FLOWERING, EARLINESS CHARACTERS AND YIELD OF COTTON PLANT VARIETY GIZA 90 (GOSSYPIUM BARBADENSE L.)

Abstract

Two field experiments were conducted at Shandaweel Agric. Res. Station (Sohag governorate), Egypt in 2008 and 2009 seasons to study the effect of two population density (43076 and 64615 plants/fed.) through four plant distributions, (10 cm. and 1 plant/hill), (20 cm. and 2 plants/hill), equal 64615 plants/fed. and (15 cm. and 1 plant/hill), (30 cm. and 2 plants/hill) equal 43076 plants/fed. and three levels of nitrogen fertilization (45, 60 and 75 kg N /fed.) on growth, flowering and earliness characters on Egyptian cotton (Gossypium barbadense L.) cultivar (Giza 90). The high population 64615 plants/fed. through plant distribution (10 cm. and 1 plant/hill) increased plant height at all ages as well as at harvest, the first fruiting node, days to first flower appearance in both seasons and days to first open boll appearance in the first season. Meanwhile, the plant distribution (20 cm. and 2 plants/fed. with the same density 64615 plants/fed.) increased days to first open boll appearance in the second season. Increasing plant spacing up to 30 cm. 2 plants/hill (43076 plants/fed.) gave the highest value of number of monopodia and sympodia branches/plant at all ages and at harvest in both seasons, number of green leaves /plant at all ages in 2008 and at 105 age in 2009, dry weight of leaves (gm) at 75, 135and 105 ages in the both seasons, dry weight of reproductive organs/plant at ages 105 and 135 in both seasons, total dry weight/plant at ages 75, 135and 105, 135 in the first and second season, respectively, leaf area per plant at age 135 in the first season, earliness percentage and number of flowers /plant, Shedding percentage of bolls in both seasons and second season respectively. While, 15 cm. 1 plant/hill with the same density gave highly significant increase number of green leaves /plant at age 75 and 135 in the second season, dry weight of leaves at 105 age and 75, 135 ages in the first and second season respectively, dry weight of reproductive organs/plant at age 75 in both seasons, total dry weight/plant at ages 105 and 75 in the first and second season respectively, leaf area per plant at age 75, 105 and at all ages in the first and second seasons respectively and number of flowers /plant, Shedding percentage of bolls in the first season. Application of nitrogen fertilizer up to 75 kg N/fed. significantly increased plant height, number of monopodia and sympodia branches/plant, number of green leaves /plant, dry weight of leaves, dry weight of reproductive organs/plant, total dry weight/plant, leaf area /plant, the first fruiting node, days to first flower and open boll appearance, number of flowers /plant and shedding percentage of bolls in the second season. While, decreasing nitrogen fertilizer up to (45 kg N/fed.) led to significant increase in earliness percentage in both seasons. Interaction between population density and nitrogen fertilizer was insignificant on all attributes studied, except, number of monopodia branches at ages 75 and 105, total dry weight/plant at age 135, the first fruiting node, number of flowers /plant and shedding percentage of bolls in the first season, dry weight of leaves at ages 75 and 105, leaf area /plant at 105 age and earliness percentage in the second season, number of sympodia branches/plant at harvest, number of green leaves per plant at ages 75 and 105 and days to first flower appearance in both seasons. For yield and yield component, increasing plant spacing up to15cm.1 plant/hill or 30cm.2 plants/hill equal(43076 plants/fed.)gave the highest value of number of open bolls and seed cotton yield/plant and boll weight in two seasons and at the first season respectively ,plant spacing at 20cm. between hills and 2 plants/hills(64615 plants/fed.)gave highly significant increase seed cotton yield and lint yield ken./fed. in both seasons and first season respectively, increasing plant spacing between hills (43076 plants/fed.) gave a significant increase in lint percentage in both seasons seed index and oil percentage in the second season .Application of nitrogen fertilizer up to high rate 75 kg n/fed. significantly increased the number of unopen bolls, boll weight, seed cotton yield, seed cotton yield ,lint yield/fed. and seed index. While, deceasing nitrogen fertilizer up to (45 kg N/fed.)led to significant increase in number of open bolls/plant and lint percentage in both seasons. The interaction between population density through plant distribution and nitrogen fertilizer was insignificant on all attributes stud, except, seed cotton yield/plant. The higher yield was obtained from the planting at (20cm. between hills and 2 plant/hill)x75 kg N/fed. in both seasons.