Linkage disequilibrium (LD)-based marker-trait association (MTA) was used to identify markers for sucrose and yield contributing traits in a panel of 108 sugarcane genotypes from sub-tropical India. Population structure (Q), kinship (K), and MTA study exploited a set of 989 marker loci generated from 123 genomic-and expressed sequence tag-SSR primers. The mixed linear model (MLM) coupled with a modified algorithm for population structure (Q) analysis was able to control both type I and type II errors and provided a deeper understanding of the genetics, population stratification and its manifestations on LD in the sugarcane genome. Significant associations were identified for four markers with cane diameter, seven markers each with cane length and number of millable canes (NMCs), eleven markers with number of nodes, six with sucrose per cent, and five markers with average cane weight. A total of 15 markers stable for all the 3 years of study explained 57 % trait variation for NMCs, 34 % for cane width, 27 % for cane length, 20 % for sucrose content, and 19 % for number of nodes. The frequent deviation of structure-based profiles from pedigree-based grouping in this complex heterozygous system reinforced the importance of using genotypic data for selection and breeding. The results contribute to a deeper insight of the complex genome and the identified MTAs could be exploited to fine-tune marker-assisted breeding programmes in genetically complex sugarcane crop.

Red rot is a serious disease of sugarcane caused by the fungus Colletotrichum falcatum that has a colossal damage potential. The fungus, prevalent mainly in the Indian sub-continent, keeps on producing new pathogenic strains leading to breakdown of resistance in newly released varieties and hence the deployment of linked markers for marker-assisted selection for resistance to this disease can fine tune the breeding programme. This study based on a panel of 119 sugarcane genotypes fingerprinted for 944 SSR alleles was undertaken with an aim to identify marker-trait associations (MTAs) for resistance to red rot. Mixed linear model containing population structure and kinship as co-factor detected four MTAs that were able to explain 10-16 % of the trait variation, individually. Among the four MTAs, EST sequences diagnostic of three could be BLAST searched to the sorghum genome with significant sequence homology. Several genes encoding important plant defence related proteins, viz., cytochrome P450, Glycerol-3-phosphate transporter-1, MAP Kinase-4, Serine/threonine-protein kinase, Ring finger domain protein and others were localized to the vicinity of these MTAs. These positional candidate genes are worth of further investigation and possibly these could contribute directly to red rot resistance, and may find a potential application in marker-assisted sugarcane breeding.

The present investigation envisaged to assess genetic variability in immunocompetence and performance traits in three pure strains of Rhode Island Red (RIR) chicken, viz. RIR S , RIR C & RIR W , and its two crosses, viz. CARI-Sonali and CARI-Debendra. A total of 3232, 1263, 346, 1278 and 1258 eggs of RIR S , RIR C , RIR W , CARI-Sonali and CARI-Debendra, were set in three hatches for performance evaluation. Single hatched out 74, 74, 72, 82 and 81 chicks of corresponding genotypes were investigated for immunocompetence status assessed through haemagglutination (HA) test, Lysoplate Assay and Single Radial Immunodiffusion assay. The data on various immunocompetence and performance traits was recorded and analyzed by least squares analysis of variance. The investigation summarized that pure strains demonstrated better immunocompetence than crosses. RIR W demonstrated highest percent fertility followed by RIR C , RIR S , CARI-Sonali and CARI-Debendra. Highest percent hatchability on total egg set basis was observed in RIR C , whereas CARI-Debendra demonstrated highest percent hatchability on fertile egg set basis. CARI-Debendra demonstrated higher body weights than CARI-Sonali followed by RIR S , RIR W and RIR C strains. CARI-Sonali pullets demonstrated (p<0.05) least AFE than RIR S preceded by RIR W , CARI-Debendra and RIR C . Pullets of crosses had (p<0.05) higher EW28 and EW40 than pure strains. CARI-Sonali pullets had (p<0.05) higher EP40 than RIR S >RIR W =CARI-Debendra>RIR C . There had been significant genotype×sex interaction effect on body weights at 2 nd , 8 th week and onwards. At 2 nd week of age, CARI-Debendra-female showed highest body weight but subsequently CARI-Debendra-males were the heaviest. Effects of hatch, sex and chick weightregression on growth traits as well as of hatch and housing weight-regression on layer production traits were significant. Crosses demonstrated least percent mortality than pure strains during brooding but reverse in laying stage.

Three hundred and three chicks of both sexes, from a synthetic dam line (SDL) of broiler chickens, were studied for economic traits (body weights at 4, 5 and 6 weeks of age) and immunological traits (humoral and cell mediated immune responses, and serum lysozyme concentration). The objective was to evaluate these traits and to estimate their genetic and non-genetic parameters. The humoral immune response was assessed by estimating the antibody response to sheep red blood cells using the haemagglutination (HA) test and serum IgG concentration using single radial immunodiffusion (SRID). The cell mediated immune (CMI) response was estimated as in vivo response to a mitogen (PHA-P). Serum lysozyme was measured by lysoplate assay. Least squares means for body weight at 4, 5 and 6 weeks were 684 +/- 20, 920 +/- 19 and 1205 +/- 28 g, HA titre was 6.289 +/- 0.246, CMI was 0.438 +/- 0.015 mm, lysozyme was 1.860 +/- 0.047 microg/ml and IgG was 6.287 +/- 0.194 mg/ml. There was an effect of sire on HA titre and on body weight at 4, 5 and 6 weeks of age; males were heavier than females. Heritability estimates were high for body weights but low for immunological traits. Phenotypic correlations (rp) among body weights were high and positive but were very low between body weights and most immunological traits. Among the immunological traits all rp were very low. Genetic correlations (rg) of body weights were positive and medium to high with CMI and HA and negative with serum IgG.

No abstract

No abstract

This investigation aimed to evaluate genetics of body conformation and feed efficiency characteristics in a selected line of Rhode Island Red chicken taking 100 numbers of single hatched out pedigreed chicks at Central Avian Research Institute (India). Data was analyzed by least squares analysis of variance. Least squares means of body weight, shank length, keel length, breast angle, body Weight Gain (WG), Feed Consumption (FC) and Feed Conversion Ratio (FCR) were estimated at various weeks of age. Sires of the chicks significantly (p<0.05) influenced the estimates of all the traits throughout the ages with a few exceptions. Chicks' sex also affected (p<0.05) the estimates of all the traits excepting 4th week body conformation traits, FC at 6th week onwards and 6th week FCR only. Male birds demonstrated better estimates than females throughout the ages. The FC and 16th week FCR also varied (p<0.05) among different feeding groups. All the traits excluding FC were heritable at variable magnitude. The estimates of genetic and phenotypic correlations coefficients were positive in trends with high magnitude among the intra-week body conformation traits and least to high magnitude among various feed efficiency traits. Only WG and FCR were invariably negatively correlated with a range of low to high genetic correlation coefficients. These research-outcomes may serve as base information to the breeders and academicians.

No abstract