Abstract

                                In a programme of breeding hybrid sorghuns, utilisation of cytoplasmic-induced male-sterile lines has great advantages. In this, however, it became necessary to study how far the stigmas are similar to the normal fertile ones in their behaviour under different environmental conditions. Floral biology has been studied in this crop by Ball (1910), Graham (1916), Ramanathan (1924), Vinall (1926), Patels (1929), Rangaswami Ayyangar and V. Panduranga Rao (1931) etc. In general, it is given that the stigmas come out first sometimes as early as 15 to 36 hours before the appearance of the stamens. Ball and Vinall record that the flowers open in the early morning hours. According to Patels it is in the forenoon from 4 A. M. Graham says it is from 11 P. M. to 4 P. M. the next afternoon. Ramanathan's findings show that the flowering period is between 1 a. M. to 4 P. M. According to observations made at Coimbatore, it varies from variety to variety. S. durra, S. roxburghii, S. nervosum commence opening their flowers at midnight and the opening continues till 8 A. M. and may get prolonged to 10 a. M. at the most. S. margaretiferrum, a sorghum from Sierra Leone Flowers from 8. 4. M. to 4 r. M. and it is recorded that a panicle takes 9 days to complete the anthesis.

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