FLOWER BUD DEVELOPMENT IN GREENHOUSE-GROWN COTTON

The determination of cotton (Gossypium hirsutum L.) bud age in days re lative to anthesis (DRA) is of value for studies of fiber differentiat ion. Bud age is easily judged at 1-d preanthesis (- 1DRA) but is less discernible in younger buds. The objective of this study was to relate bud length to bud age relative to anthesis and to determine the effec t of bud position on bud length. 'Stoneville 506' cotton was grown in a greenhouse in 4-L pots of potting mixture. Data were taken from 48 p lants planted 14 Mar. 1991. Bud length was measured from the midpoint of the base of a bract to the tip of the corolla whorl. Mean bud lengt h at - 1DRA peaked at 3.2 cm at main-stem node (MSN) 10 for the first sympodial node (Position 1 buds) and at 3.0 cm at MSN 8 for Position 2 buds. Also, mean bud lengths at Positions 2 and 3 on sympodial branch es below MSN 9 were as long or longer (P less than or equal to 0.05) t han mean lengths at Position 1, but a reverse trend of Position 1 buds being longer than Position 2 buds was observed from MSN 9 through 13. The peaks in length for Position 1 and 2 buds were indicative of a pe riod of maximum bud growth around 94 days after planting that impacted buds at both positions simultaneously. Bud length was correlated with bud age only at - 2DRA and - 1DRA and was affected by sympodial posit ion and MSN as well as by the interaction of sympodial position and MS N.