Indian Agricultural Statistics Research Institute

About: Indian Agricultural Statistics Research Institute is a facility organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Small area estimation. The organization has 454 authors who have published 870 publications receiving 7987 citations.

Variant forms of qualitative traits of indigenous chickens reared under extensive system in Tolon District, Ghana

Abstract: Context Rural chicken production in most developing countries is based mainly on scavenging systems with indigenous chickens that have not been properly characterised and classified into well-defined breeds. Aims This study was conducted to identify the variant forms of qualitative phenotypic traits of local chickens in Tolon District, northern Ghana. Methods About 320 adult birds were sampled and data collected by using observation and a chicken colour chart. Traits included head shape; comb type, size and colour; feather distribution; and earlobe, eye, plumage, skin and shank colours. Chi-squared goodness of fit test was used to test whether variant phenotypes of each qualitative trait were equally distributed. The hypothesis of no associations between pairs of traits was tested by using Cramer’s V. Key results There were highly significant (P < 0.01) differences in the distributions of variant phenotypes of all traits. The main comb type observed was single (85.9%), followed by pea (8.8%) and rose (5.3%). A majority of birds had small combs (57.8%), although others had medium (28.4%) and large (13.8%) combs. Females had small to medium combs, whereas males had medium to large combs. A majority of the chickens had white earlobe colour (60.3%), followed by pied red and white (22.5%). Feather distributions observed were normal feathered (84.4%), naked neck (8.4%) and frizzled (7.2%). Five plumage colours were observed, although some were in combinations. White plumage was the most common (22.5%), followed by black (18.8%), with brown/ash the least common (0.03%). Community was significantly (P < 0.01) associated with comb type, size and colour, and eye, shank and skin colours. Also, comb size was significantly associated with sex and comb type. Conclusions Generally, local chickens exhibited heterogynous phenotypes for qualitative traits. Local chickens in the district could be described as normally feathered with wide variation in plumage colours and having mainly single comb type. Implications The knowledge of these variant phenotypes and their associations will serve as baseline information for the characterisation and conservation of local chicken types. It could also provide guidelines in selecting bird ecotypes and/or communities for breed improvement programs in the study area.

Response to selection under non-random mating. II : Prediction

Abstract: A general expression for response to selection appropriate for both random and non-random mating situations is derived and illustrated with full-sibbing.