GROWTH, REPRODUCTIVE AND YIELD RESPONSES AND OIL CONTENT OF ETHIOPIAN MUSTARD (Brassica carinata A. Braun) GENOTYPES AT DIFFERENT ALTITUDES

Abstract

Ethiopian mustard (Brassica carinata A. Braun) is an important vegetable and oil seed crop in the highlands of Ethiopia. The crop has attracted a lot of interests in recent years due to its potential as a feedstock and as a biofuel crop. However, there are little research effort towards the crop in terms of productivity and optimized agronomic requirements. The seed and oil yield of the crop is constrained by a number of factors among which the growing climate is the paramount factor. Therefore, a pot experiment was conducted at three locations with varying altitudes to investigate the impact of altitude on phenology, reproduction, growth, yield and oil content of 11 Brassica carinata genotypes. The study was conducted from January 2011 to June 2011, at three altitudes i.e. high (Bale Goba, 2743 masl), mid (Arsi Negele, 2043 masl) and low (Dilla, 1416 masl)) under irrigated condition using 11genotyp of Brassica carinata which resulted in 33 treatments. The factorial experiment was laid out in a completely randomized (CRD) design with three replications as pot experiment in a controlled edaphic condition. Data were collected on phenological and reproductive traits, growth parameters, yield and yield related traits and oil content. The result of the study revealed that interactions between altitude and genotype very highly significantly (p<0.0001) influenced all characters, except number of leaves per plant and pod length which were only influenced by the main factors. Increasing the altitude from low to high delayed the time for all the studied phenological traits. As a result, the number of days for 50% emergence, 50% flowering and 90% maturity were increased from 6.33 to 17.67, 50 to 107.33 and 92.67 to 147 respectively and the earliest genotypes to attain days to 50% emergence and days to50% flowering were 23601 respectively. The genotype to attain shortest days to maturity (92.67 days) was genotype 21338 at lower altitude. Reproductive traits showed an increase with increasing altitude. Hence the highest flower number per plant (218.6) was attained from genotype 23601 at higher altitude. Similarly Yield and yield components are also increased with increasing altitude. The maximum seed yield per hectare (194556Kg) was recorded from genotype 23601 at high altitude followed by the genotypes 202488(1538.89Kg) and 215187(1503.33Kg) at mid altitude. The highest oil percentage (41.79%) was recorded from genotype yellow dodolla at the same altitude. Hence, from the result it can be concluded that, high and mid altitudes respectively were appropriate to maximize Brassica carinata seed and oil yield. However, since the experiment was done only for one season and with limited number of genotypes repeating the experiment over different seasons with more number of genotypes at field condition will be demanding to come up with plausible recommendation.