Impacts of Variation in Agroclimatological Indices and Crop Combination on Growth and Yield Response of Okra in Mixtures in a Forest-Savanna Transition Zone of Nigeria.

Abstract

Impacts of variation in agroclimatological indices and crop combination on growth and yield response of okra in mixtures with two sorghum cultivars and maize in a forestsavanna transition zone of Nigeria was investigated at the Experimental Research Farmland of the National Horticultural Research Institutes (NIHORT), Ibadan during the 2009 and 2010 cropping seasons. Plants phenological stages formed the basic unit of time for the investigation. During these phenological stages, agroclimatological thermal and moisture indices were measured daily and processed into ten-day (decadal) averages likewise selected agronomic growth and yield parameters of the components crops were taken fortnightly. The results showed that the 2010 season crops had relatively longer growth duration, received more rainfall than 2009 season (692mm vs 487.2mm) while 2009 experienced warmer temperature during establishment and early vegetative stage than 2010 season ( 33.2°C vs 32°C), and (28.5°C vs 27 °C) during the reproductive phase for 2009 and 2010 season respectively. The mean pod yields of okra in both seasons were dependent on crop combination since pod yield in sorghum cultivars mixtures (Farin Dawa and Janare) (97.33 and 93.67 pods) was significantly higher than in maize mixtures (58.33 and 49.65 pods) in 2009 season likewise in 2010 season when okra pods in sorghum mixtures (Farin Dawa and Janare) had (309.67 and 232.33 pods) against (162.67 and 67 pods) in maize mixtures for the two sorghum cultivars. The lower pod yield in 2009 season can be attributed to a higher frequency of a 5-day dry spell during flowering stage which led to a condition of moisture deficient, reduced pollination or cause spikes to dry out and heavy flower abortion. Also, it took okra pods longer to reach marketable size in the 2009 season than 2010 season (i.e. 5-9 v. 2-6 days).