Study on reproductive performance of Holstein–Friesian dairy cows at Alage Dairy Farm,Rift Valley of Ethiopia

A retrospective study was carried out to evaluate the reproductive performance of Holstein–Friesian cattle in Alage Dairy Farm in the Rift Valley of Ethiopia using data recorded from July 1983 to June 2005. Data of cows with complete information were considered, and a total of 1,104 records for calving to conception (Cal-Con), calving interval (CI), and number of services per conception (NSC), and 721 records for age at first service (AFS) and at first calving (AFC) were analyzed. The overall means (±S.E.) of AFS, AFC, Cal-Con and CI, and NSC were 991.4 ± 24.3, 1,265 ± 24.3, 285.8 ± 18.9, 561.3 ± 18.9 days and 1.69 ± 0.1, respectively. Parity significantly influenced NSC, Cal-Con, and CI. Season and year showed a significant effect on all the parameters, indicating the role of the environment and more specifically the influence of nutritional conditions at least for the long AFS and AFC, management practices, and climate on reproductive performance of the study herd. A more focused study to discern the elements of the reproductive constraints have been recommended.     

African nightshades: genetic,biochemical and metabolite diversity of an underutilised indigenous leafy vegetable and its potential for plant breeding

African nightshades are becoming more important as leafy vegetables in sub-Saharan Africa. Previously considered as food for the poor, their cultivation is now being promoted, and some cultivars are commercialised; however, most farmers use self-produced seeds, leading to low and varying yields. Improvement through conventional breeding depends on the available genetic diversity, the possible breeding systems, and the nutritional value of the accessions. Therefore, we review the information on these topics with the following main outcomes: the most commonly discussed species, S. nigrum, S. scabrum, S. villosum, and S. americanum, could be differentiated using molecular markers, but further sub-clustering was rarely possible, and statistical support often missing. S. nigrum and S. scabrum seem to be most closely related to each other. The mainly self-pollinating African nightshades form a polyploidy series with diploid (2n = 2x = 24) to hexaploid taxa. Interploidy hybridisations between diploids and tetraploids are possible, whereas the hexaploid S. nigrum and S. scabrum could not be crossed to genotypes of lower ploidies. Solanine, solamargine, solasonine, and chaconine are the major steroidal alkaloid glucosides in African nightshades. Amounts are age and environment dependant. Mineral and vitamin contents in leaves are at least as high as in Brassica oleracea or Spinacia oleracea, underlining their relevance as local vegetables.     

Exploiting the diversity of barley landraces in Ethiopia

The paper describes a methodology to incorporate the collection of barley landraces available in the Plant Genetic Resources Centre of Ethiopia (PGRC/E), as well as future collections, in the Ethiopian barley breeding program. Six hundred pure lines extracted from thirty Ethiopian barley landraces were evaluated and selected, along with the original populations, between 1989 and 1993. Three lines were identified which significantly outyielded the local landrace in some of the testing sites and had a higher average yield across sites and seasons. The yield of these lines was similar to the best improved variety also developed from a landrace population. Despite the relatively small number of landrace-lines (600) in the original population, the exploitation of the diversity existing within Ethiopian barley germplasm has produced in only five years promising lines for yield at low input conditions and for disease and insect resistance. Some lines had a yield potential comparable with the best breeding lines produced earlier, and one is under multiplication for release.     

Heterosis and heritability in crosses among Asian and Ethiopian parents of hot pepper genotypes

Hot pepper is the most important worldwide grown and consumed spice and vegetable crop. Though hybrid breeding has been proposed for genetic improvement in the crop, but there is lack of information on heterosis in crosses among crop genotypes in Ethiopia. Twelve genotypes (nine Asian and three Ethiopian parents) of hot pepper were crossed in 2003 cropping season in a half-diallel fashion to fit Griffing’s fixed effect model analysis. An open field experiment was conducted in 2004/2005 to investigate heterosis for fourteen traits in 66 F₁ hybrids grown together with their 12 selfed parents. Highly significant genotypic differences were observed for all the traits except for leaf area. Variance component due to specific combining ability (dominance) were larger than that due to general combining ability (additive) for each of the studied traits with few exceptions. Broad sense heritability (H _b²) for fruit traits were more than 60% and with wide gap from narrow sense heritability (h _n²) for most of the important traits like number of fruit per plant (H _b² = 88.3% and h _n² = 46.0%), days to maturity (H _b² = 87.2% and h _n² = 23.1%) and dry fruit yield per plant (H _b² = 72.6% and h _n² = 14.6%). Maximum heterosis over mid-parent and better-parent, and economic superiority of hybrid over standard check were recorded, respectively for dry fruit yield per plant (163.8, 161.8 and 92.1%), number of fruits per plant (104.4, 79.6 and 136.4%) and days to maturity (−29.8, −31.5 and −23.6%). These observations suggested a possibility of utilizing dominance genetic potentiality available in diverse genotypes of the crop by heterosis breeding for improving hot pepper to the extent of better economic return compared to the current commercial cultivar under production in the country. Low narrow sense versus very high broad sense heritability for days to maturity and dry fruit yield per plant could be a sign for achievability of earliness and high fruit yield using heterosis in hot pepper. The maximum heterobeltiosis were recorded either from F₁s obtained from Ethiopian and Asian crosses or from within Asian crosses, suggesting the possibility of maximizing heterosis by considering genetically diverse parental genotypes. The manifestation of highest heterosis in hybrids from among Asian lines indicated existence of genetic diversity among Asian genotypes and the potentiality for improvement of hot pepper using genotypes from different regions of the world along with elite inbred lines from local cultivars.