A review on seed physiology and chemical composition of cotton (Gossypium spp.)† Singh V. P.1,3,*, Maiti R. K.2 1Gaurav Publications, Agricultural Research Information Centre Systematic Printers, Near Video Market, Hisar-125 001 (Haryana), India 3Professor of Agronomy (Retd.), CCS Haryana Agricultural University, Hisar-125 004 (Haryana), India 2Honorary Professor, Departamento de Quimica y Biologia, Universidad de las Americas-Puebla, Santa Catarina Martir, Cholula, C. P. 72820, Puebla, Mexico *(e-mail: cropresearch1@gmail.com)
†Reproduced from Crop Res., Hisar Vol. 29 (3): 339–365 (2005). Online published on 30 June, 2017. Abstract The present paper makes a brief review on research trends on various aspects of seed quality, chemical composition and factors affecting germination, seedling emergence and seedling vigour in cotton. Considering pollen viability to be most essential for efficient cross pollination, an efficient in vitro technique is developed to test pollen viability. During seed development, several biochemical changes occur, but ecological conditions have great influence on chemical composition. Owing to high lipid contents, cotton seeds are utilized as animal feed for carp, broiler chickens, etc. Different factors affect germination and seedling vigour. Seed viability decreased linearly during the storage period, but seeds treated with chemicals gave superior germination and vigour than control. Allochemicals promoted plant growth at lower concentration, but inhibited at higher concentration. Heavy metal Cd inhibits seedling germination. Under natural storage, the decrease in germinability is associated with changes like increased accumulation of total peroxide and malondialdehyde content and decreased activities of antioxidant enzymes peroxidase, catalase, ascorbate peroxidase, glutathione reductase and superoxide dismutase. Conservation tillage improved cotton germination, emergence, dry matter and lint yield. High density usually gave faster and more uniform rates of radicle emergence than low density ones. Seedlings from heavier seeds gave greater rates of accumulation of fresh and dry weight, and quality and vigour indices were higher than those from light seeds. Chemical treatment with imidacloprid+tolylfluanid+ pencycuron gave better physiological quality than the other treatments. Different abiotic factors affect germination, emergence and seedling vigour in cotton and the germination rate and percentage germination of the cotton seeds, exposed to high and low temperature, salinity, water stress, etc. It was confirmed that osmotic priming with polyethylene glycol is not effective in the case of cotton. The germination count, seedling dry weight decreased with decrease in moisture content of soil. Waterlogging decreased germination and shoot growth, while root length increased. It was reported that pre-sowing in potassium humate (PH) solution (55% humic acid, 30% fulvic acid and 8% potassium hydroxide) gave good seedling growth and good stand in the field. Increase in salinity decreases germination and seedling growth in cotton, but pre-soaking in salinity solution improves salinity tolerance in cotton. In addition, the percentage and rate of seed germination and percentage of normal seedlings were increased by increasing both salinity and drought levels. Salinity induced changes in alpha-amylase and protease activities and associated metabolism in cotton varieties during germination and early seedling growth stages. Salt tolerance of cotton plants at seedling emergence stage may be ameriolated/regulated by soaking seeds in Pix (DPC) and CaCl solutions. Cotton seeds are infested with several fungal pathogens, affecting thereby germination and seedling emergence, but different ameriorative measures are adopted to prevent the incidence and gravity of fungal pathogens viz., additions of graphites with fungicides. It was assessed that the synthesis of phenolic compounds induced by infection with Fusarium is associated with the mechanism of resistance. Seed germination and seedling growth were best and fungal infection lowest with encapsulation with gypsum+bentonite or Sepiret 6182 combined with fungicides. Top Keywords Abiotic, biotic, chemical composition, cotton, fungal pathogens, germination, salinity, seed development, seed treatment. Top |