Performance of inter specific cotton hybrids under various plant geometries and nutrient levels

Abstract

Cotton is known as white gold and queen of fibers. It is an important cash crop of global significance which plays a dominant role in world agriculture and industrial economy. India is important grower of cotton on a global scale. The cotton productivity in 2016-17 has 568 kg/ha with an area of 105 lakh ha and production 351 lakh bales each 170 kg [1]. Plant geometry is having greater importance in cotton cultivation. Bt cotton crop may be producing excessive vegetative growth at wider plant geometry and excessive reproductive growth at close plant geometry. However, numerically lower monopodial with closer plant geometry and lower sympodial with wider plant geometry were observed indicating more period under vegetative growth with wider spacing [2]. Closer plant geometry also recorded higher seed cotton yields [3]. Cultivar selection, a key management component in any cropping system, is even more critical in various crop geometry of cotton production. While high yield potential is a predominant consideration, maturity, plant size, the transgenic present, and fiber properties are also major factors to consider [4]. The maximum exploitation of these genotypes can be achieved only after determining their optimum planting densities in comparison to recommended cotton varieties. In general, it was observed that lower plant densities produces high values of growth and yield attributes per plant, but yield per unit area was higher with higher plant densities [5]. The reasons for decreasing productivity are due to decreasing soil fertility especially micronutrients, imbalanced use of fertilizer and occurrences of physiological disorders like square dropping, square drying, leaf reddening etc. Among these, imbalanced use of major and micro nutrients is the major problem [6]. To overcome these constraints, additional nutrition through foliar feeding is required over and above the normal fertilizer recommendation. This is one of the most efficient ways of supplying essential nutrients to a growing crop. Newly released, high yielding transgenic cotton cultivars are said to have a higher nutrient demand during the boll development period (between flowering and maturity) due to their higher boll retention rate and larger boll load than conventional cultivars [7].