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A Revised Version of Cotmap for Mapping Cotton Plants

C.E. Watson, Jr. and F.M. Bourland


 
ABSTRACT

Due to its indeterminate growth habit and multiple fruiting sites, plant map data of cotton (Gossypium hirsutum L.) are difficult to collect and interpret; however, such data is valuable for describing genetic variation and explaining variations in yield among genotypes or production practices. The COTMAP program (Watson and Bourland, 1989) was developed as a tool to aid research scientists in the summarization and analysis of plant mapping data for cotton. The COTMAP technique requires individual mapping of the first and second sympodial positions; however, other fruiting sites are measured collectively in three categories: 1) bolls on outer ( > position 2) sympodial nodes, 2) bolls on sympodia arising from monopodia, and 3) bolls on secondary axillary (either on main stem or sympodial nodes) positions (Bourland and Watson, 1990). Plant height, number of monopodia, node number of the first sympodial branch and the highest sympodial branch with two nodes are also recorded to aid in the evaluation of plant structure. The concept is based on the relative importance of the first two sympodial positions. Several researchers have reported that 80 % or more of the yield of a cotton plant is produced on the first two sympodial nodes from the main axis (Kerby et al., 1987; Mauney, 1979 and 1986). This technique of mapping saves considerable time compared to mapping each fruiting site individually with little loss of information.



Reprinted from Proceedings of the 1997 Beltwide Cotton Conferences pp. 477 - 478
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998