PHYSIOLOGICAL RESPONSES OF SPRING WHEAT CULTIVARS GROWN IN WARM AND COOL ECOTOPES

Abstract

Rising levels of atmospheric temperatures in growing ecotopes are thought to affect physiological functioning of plants. Four wheat cultivars, UNZA II (heat tolerance), Loerie II (check), Nduna and Pungwa were tested in both warm and cool ecotopes for their acclimation capacity to subsequently enhance production. Using five replications, a randomised complete block design was used and data on canopy temperature (CT), stay green duration (SGD) and dry matter production and accumulation (DM) was collected and analysed using GENSTAT software version 18. Results revealed that all cultivars had 3oC low CT than their temperatures in cool ecotope in 2014 and 3oC to 6oC high CT than their cool ecotope in 2015. Cultivars terminated their DM production and accumulation in the warm ecotope 7 days earlier than in cool ecotope. DM production and accumulation was quick in 2014 and slows in 2015 in the warm compared to the cool ecotope. Pungwa showed superiority with 52.8% SGD and 39.8% SGD remaining at 28 days after anthesis in 2014 and 14 days after anthesis in 2015 in the warm ecotope, respectively when other cultivars had lost over 65% and 76% of the SGD and maintained its DM at physiological maturity in both seasons. Pungwa with longer SGD, low CT and more DM accumulation suggests the ability to support plant growth and could enhance wheat production in warm ecotope.