Breeding for Glandless cotton

Abstract

After the discovery of glandless genes by McMichael (1954), the development of cotton varities without gossypol become possible. Those varieties would be able to play an importance role in the near future to help solve problems of human food. Considering the importance of these varieties a project ‘Breeding for glandless cotton’ with the financial assistance of Pakistan Science Foundation was initiated at Cotton research institute, Sarkrand in May 1996. As per approved the plan of work of the project, hybridization program was initiated during August and September 1996. Twelve exotic lines were kept as female parents while CRIS-133 and CRIS-134 were used as pollinators to induce high yield, early maturity, heat resistance, high ginning outturn percent from these pollinators. The successful bolls from thirty cross combinations were picked, ginned and sown on 7th May 1997 as F1 along with their respective parents. unfortunately, out of thirty combinations are the rains. Nevertheless the single plant selections were done and the 14 single plant progenies were picked and sown as F2 generation in the green house on November 15, 1997. Up to 5th of May 1998 opening of bolls in some of the combination was started. Thus the open bolls will be picked to raise F3 generation in the end of may or first week of July 1998. Fresh crosses were attempted this year also as suggested by learned referee, locally adapted cotton leaf curl virus cultivars were sown as female parent and exotic glandless lines as male parents. The crosses were attempted in 21 cross combination but the successful bolls were harvested in 11 combination. From these 11 cross combinations made between cotton leaf curl virus resistant and glandless exotic parents, 35 single plant progenies were selected and sown along with two commercial checks during May 1998. Due to very limited space in green house only five combinations were raised as F2 on November 15, 1997.the bolls from these combinations were picked and sown as F3 on 3rd June 1998. Single plant selection for high yield and glandless character were made. In all 20 single plants progenies were selected from these five cross combinations (four from each combination). These progenies will be sown in May 1999 as F4 generation. As indicated in future plans of work in first annual research report, the cottonseed of sixteen advance strain developed by CRI, Sarkrand was sent to Pakistan Institute of Cotton Research and Technology, Karachi to test its quality for use as human as well as diary food. Unfortunately the equipment used for gossypol determination was out of order hence the results could not be received (the results are still awaited) The learned referee while offering comments on first annual report had suggested ‘developing cotton plants with maximum glands body but minimum or free gossypol in the seed’ the phenomenon is called ‘delayed gland morphogenesis’, a character mainly noted in certain species. the initial cells for gland formation occur in the seed embryos, but there is no deposition of gossypol until they begin to germinate. All other aerial portions of the cotton plant (leave, stem bolls) have as many glands and as much gossypol as present in commercial varieties. The cutting of wild species like Gossypium bickii, Gossypium austral and Gossypium sturtianum having gossypol glands reduced or absent from the embryos while generally present in other plant parts were brought from CCRI, Multan and were grown in the filed during February 1999.