Nigerian Journal of Genetics最新文献

A study on the distribution and frequencies of coat colour, wattle, beard, horn, and hair type using 375 extensively managed local goats was carried out in the three administrative zones of Niger state, Nigeria. The animals were scored for coat colour pigmentation pattern, presence or absence of wattle, beard, horn, hair type and extra teat. The study showed that light brown is the predominant colour in zones A (43.24%) and zone C (47.57%). Dark brown colour was predominant in zone B (37.82%) followed by light brown (31.09%). The observed frequencies for wattle (Wa^w) and extra teat (Et^e) were above (p < 0.01) the expected Mendelian value of 75% for a dominant gene in all the zones (90.34, 86.55, 87.39 percent for wattle and 91.73, 96.64, 98.21, percent for extra teat in zones A, B, and C, respectively). The gene frequency for beard (Br^b) were significantly lower (p < 0.01) than the expected Mendelian value of 75% for a dominant gene in zone A (66.20%) and zone B (55.46%), but was higher in zone C (83.78%). The gene frequency for polledness (Po^p) was 0.00% for all the zones. The gene frequency for soft hair.

was more than (p < 0.01) the expected Mendelian value of 75% for dominant genes in zone C (87.33%) but fell short in zone A (60.69%) and zone B (43.70%), respectively. It was concluded that coat colour variation exist in local goats reared extensively in Niger state.

Gene action and interaction are very important in formulating the appropriate breeding technique to produce new varieties in okra. The objective of the study was to investigate gene action controlling yield and 12 related traits in okra. Sixteen bi-parental progenies of okra were evaluated in October, 2013 and May, 2014 at the Federal University of Agriculture, Abeokuta (Lat 7°29 N, Long 3°30 E), Nigeria. Seeds were sown in single-row plots laid out in randomized complete block design with three replicates. Mean squares were obtained for the thirteen characters according to North Carolina Design II. Heritable variances were partitioned into additive and dominance components. General (GCA) and specific combining abilities (SCA) of both parental and progenies respectively were estimated with a view to identifying high combiners among genotypes. Results suggested both additive and dominant gene effects for most characters with dominant gene effects for number of leaves per plant and weight of 100 seeds. The study concluded that both additive and dominant gene actions controlled the expression of characters in okra. NHGB/09/009A and FUNAAB-11-8 are high combiners for number of days to 50% flowering and number of pods/plant and they are recommended as high-yielding, early-maturing okra variety. FUNAAB-11-4 x LD 88 and UI4-30 x FUNAAB-11-8 can be further improved to develop high-yielding hybrid okra varieties due to their high SCA. Number of days to 50% flowering, plant height, number of branches per plant, pod weight and number of ridges per pod will respond to selection because of the preponderance of additive gene action.

The morphotypes and chromosome numbers of Euphorbia hyssopifolia and Euphorbia heterophylla from Ile-Ife, Nigeria are reported for the first time. Mitotic studies carried out on both species revealed a diploid chromosome number of 2n = 12 and 2n = 28 respectively. The results indicate that the two Euphorbia species studied belong to the members of the genus Euphorbia with the secondary system of basic chromosome number of X = 6 and X = 7 (respectively) resulting from aneuploidy and polyploidy.

Immature embryo-derived callus is more efficient for plant regeneration in maize but appears difficult to obtain in all seasons of the year compared to mature embryos from dry seeds which are readily available throughout the year. This study investigated the effect of seed size on in vitro seed germination, seedling growth, callus induction and plantlet regeneration, as well as the relationships between these parameters in five maize varieties. Seeds were designated either as large or small for each variety based on its 100-seed weights, while seed germination were obtained in petri-dishes placed between two sheets of pre-wetted filter paper. Seeds were disinfected, and mature embryos were excised from the maize endosperm and inoculated on the Murashige and Skoog salt (MS medium) supplemented with 30 g/l sucrose, 8 g/l agar, 0.1 g/l myo-inositol and 3 mg/l 2,4-D for callus induction, while embryogenic calli were transferred to medium containing 0.5 mg/l Benzylaminopurine (BAP) and 0.5 mg/l Kinetin for plant regeneration. The study showed that large seed size had significant effect on almost all the traits studied, while positive and significant correlations were observed between in vitro germination, seedling growth, callus induction and plantlet regeneration. It can be concluded that callus fresh weight may be used as a marker for improving regeneration efficiency in maize. The results from this study suggest that genetic control of in vitro regeneration from maize mature embryo can be utilized to determine inherent genotypic potentials of maize varieties with tissue culture traits for maize improvement.

Records of 224 kits produced by fifteen dams and five sires were used to estimate covariance and correlations of litter traits in composite breed rabbit using paternal and maternal half-sib method. The traits studied were total litter size at birth (TB), litter size born alive (BA), litter birth weight (LBWT), 7-day body weight (7BWT), 21 day body weight (21BWT) and weaning weight (42BWT). The analysis of variance was done in a nested design with equal number of subclass. The estimates of covariance were generally low 0.002 and 0.004,0.004 and 0.009,0.001 and 0.001 for LBWT and BA, TB and 7BWT, LBWT and 42BWT while positive and significant genetic correlations (rG) (P > 0.05) was obtained for LBWT and BA (0.94 and 0.67), BA and 42BWT (0.89 and 0.61), LBWTB and 21BWT (0.88 and 0.63) from sire and dam components respectively. Phenotypic (rP) and environmental (rE) correlations between the traits studied were mostly non-significant (P < 0.05). This report shows that there exists positive genetic correlation/relationship between litter size at birth and litter weight at weaning.