Effect of Concentration and Spraying Time of Brassinolide on Physiological Traits, Yield and Quality of Sunflower Genotypes

Abstract

A field experiment was conducted at spring season for 2019 and 2020 year at a research station of the College of Agriculture in AL_Hamudhya - Ramadi District - Anbar Provence, at latitude ○ 27 ○ - 30 N, longitude ○ 37 43 ○ - E, and elevate 49 m. above sea level, Aim to study effect of concentration and spraying date of Brassinolide BR1 for two different dates upon growth, yield, and quality for three sunflower genotypes. The experiment was carried out in a split-split-plot arrangement according a completely randomized block design (R.C.B.D.) with three replications in a total of 72 experimental units. . Where varieties (Ishaqi 1, Akmar, and Sakha) represented the main plots, the spraying dates at (bud stage, and flowering beginning) represented sub-main plots, while concentrations (0, 0.5, 1, and 1.5) mg.l-1 were the most important in the sub-main plots. The main results of the experiment were summarized as follows: 1- Brassinolide significantly affected most of studied traits, as the concentration1.5 mg L-1 at both seasons attained highest mean of plant height, plant growth rate, net photosynthesis, fertility ratio per seed (92.73 and 94.88%), seeds number per disc (750 , 1134 seeds.Disc-1), and yield of seeds per unit area (3108.0, 4763.9 kg. ha-1) respectively. Oil percentage per seeds at first season (44.94%). Concentration 1 mg L-1 attained highest percentage of Oleic acid (42.61, 43.02%) and Linoleic acid (31.63, 30.25%). concentration 0.5 mg L-1 achieved the highest percentage of oil per seeds at second season (48.87%). 2- A date of spraying growth regulator significantly affected most of the studied traits, as the first date (bud stage) attained a highest mean of plant height, crop growth rate, net photosynthesis, number of seeds per disc (645.9 , 1080.14), and seed yield per unit area (2518.7 and 4466.2 kg h-1) as well as the biological yield, while the spraying date had no significant effect on oil percentage and fatty acids formed from it. 3- Varieties have significantly differed in most studied traits, as Sakhi attained highest of leaf area mean, crop growth rate, net photosynthesis, seed fertility ratio to both seasons, number of seeds per disc (664.5 seed disc-1), seed yield per unit area (2565 kg ha-1),oil amount at first season, and linoleic acid percentage at two seasons, while Akmar gave the highest of oil percentage at two seasons (46.59, 50.33%), highest weight mean for 1000 seeds, seeds yield, and oil amount at second season , as well as superior unsaturated fatty acids percentage and the percentage of oleic acid at two seasons . While Ishaqi 1 superior in 1000 seeds weight at first season, and saturated acids percentage at two seasons. 4- An interaction between varieties and brassinolide concentrations significantly affected most of the studied traits, as Sakhi variety with a 1.5 mg L-1 concentration attained highest of stem diameter mean, growth rate, net photosynthesis, and a seeds number per disc (809, 1157 seed disc-1) at both seasons. A highest seed fertility ratio (95.64%), seed yield (3367 kg ha-1), and oil amount were at first season. as for interacting 1.5 mg L-1 with Akmar accomplished at second season a highest of seed fertility ratio (95.63%), seed yield (4905 kg h-1), and oil amount whereas the same variety with a concentration 1 mg L-1 attained the highest oil percentage for oleic acid and unsaturated fatty acids at both seasons. 5- An interaction between brassinolide spraying dates and varieties were significant in most of the studied traits, as Sakha variety with first spraying date ( budding stage) gave highest leaf area and seeds number per disc at both seasons, and highest seed yield (2809.8 kg ha-1) and oil per unit area at first season. As for interacting Akmar with first date spraying at second season gave a highest weight of 1000 seeds mean (64.08 g), seed yield (4609 kg ha-1), and oil (2320.2 kg ha-1). 6- The interaction of brassinolide spraying dates at flowering bud with a concentration 1.5 mg L-1 accomplished highest plant height mean, seeds number per disc (833.1 , 1168.6 seed disc-1), 1000 seeds weight (65.08 , 64.62 g), seed yield per unit area ( 3587, 4979 kg h-1), and the percentage of unsaturated acids (75.80 , 75.40%). 7- The triple interaction between the studied factors have significantly affected most of studied traits, as Sakha at first season and Aqmar variety at second season with a 1.5 mg L-1concentration at first spraying date recorded highest of seeds fertility ratio percentage (97.28, 96.03%), seeds yield per unit area (3846.0, 5127.7 kg ha-1) and oil amount, Ishaqi1 variety with a 1.5 mg L-1concentration at first date recorded the highest 1000 seeds weight mean (68.93, 66.50 gm) for the two seasons respectively.