Floral biology anthesis and fruit development in drumstick (moringa oleifera lam.)

Abstract

A study was conducted at College of Agriculture, Vellayani during 2001-2002 to gather information on floral biology, anthesis and fruit development in drumstick (Moringa oleifera Lam.). Sixty bearing plants were utilized for the experiments carried out during June 2001 to May 2002. Flowering was observed throughout the year except in the month of November and December. Two flowering peaks viz., July - August and February - March were recorded. The fruit production peaked during July - August and March - April. Flower buds took an average of 29.8 days or 472.25 degree days for its complete development during rainy season and 24.8 days and 471.18 degree days during summer season. Anthesis continued throughout the day with two peaks at 14 hand 04 h. Anthers were of closed type at the time of anthesis and they dehisced later. Stigma was receptive a day prior to opening and continued up to the day of opening with maximum receptivity. The pollen grains w~re spherical with smooth ex me and had three germpores. The average diameter of fertile and sterile pollen grains was 43.5 urn and 33 urn respectively. The average pollen production per anther in rainy and summer seasons was 7250 and 7500 respectively. Pollen grains exhibited highest germination and tube growth in 15 per cent sucrose medium. Viability on acetocarmine staining and germination was 97 and 88 per cent respectively. The pollen grains stored under refrigerator lost their viability within seven days while under room temperature pollen lost viability within three days. The drumstick was found cross pollinated and entomophilous. Honeybees were the chief pollinators. Insect activity was maximum 60 between 10 and 14 h. Natural pollination per cent was maximum in March and minimum in September. An average of 5.55 and 5.00 days were taken for fruit set in rainy and summer seasons respectively. Flower shedding percentage was 92.73 and 88. 60 in rainy and summer seasons. The fruit maturity per cent was 2.7 and 3.7 during these periods. During rainy season, fruits took an average of 42 days or 635 degree days for horticul tural maturity whereas 70 days or 1112.15 degree days required for physiological maturity. In summer season, fruits attained horticultural maturity in 34 days and physiological maturity in 59 days. Degree days requirement for these was 634.65 and 1111.68 respectively.