Inheritance of Compact Growth Habit, and Investigation of Linkage to Weeping Architecture and Purple Leaf Color in Eastern Redbud (Cercis canadensis L.)

Eastern redbud (Cercis canadensis L.) is a commonly used small landscape tree. Compact growth, purple leaf color, and weeping architecture are three popular ornamental phenotypes. Inheritances of weeping architecture and purple leaves have been reported previously. Inheritance of compact growth habit and its genetic linkage with the weeping and purple leaf genes have not been reported. In the present research, the inheritance of compact growth derived from ‘Ace of Hearts’ was explored in the F1, F2, and reciprocal backcross families resulting from the controlled hybridization of ‘Ruby Falls’ (normal growth/weeping architecture/purple leaf) × ‘Ace of Hearts’ (compact growth/nonweeping architecture/green leaf). All 27 F1 individuals were nonweeping, green-leaved, and noncompact. A total of 572 F2 progeny were obtained, and subsequent analysis of segregation revealed a single recessive gene controlled compact growth habit. Analysis of reciprocal backcross families confirmed this result as well. Weeping architecture and purple leaf color were also controlled by single recessive genes, confirming findings presented in previous studies in another redbud family. No linkage between the three genes was detected. This research is the first to report the inheritance of compact growth in eastern redbud and confirms independent assortment between the compact, purple leaf, and weeping genes.

Effect of feathering genes on growth performance of F2 backcrosses and comparison of F1 and F2 crosses of Abor Acre broiler breeder x native chickens in humid tropical environment

This study was conducted to evaluate growth performance, brooding and rearing mortalities of F2 main and reciprocal backcross progenies of Abor Acre broiler breeder x native chicken crosses and to compare their F1 and F2 backcross progenies. The base population used in the study consisted of mature (~ 48 weeks) male and female native chickens and exotic (Abor Acre) broiler breeder parent stock. The native chicken varieties were made up of normal feather, naked neck and frizzle genotypes. These birds were mated to the Abor Acre broiler parent stocks in main and reciprocal fashion generating F1 main and reciprocal crossbreds. Females of these F1 hybrids were then mated back to the broiler breeder cock to generate F2 main and reciprocal backcross progenies that were evaluated in the present study. Data analyzed include body weight (BWT) and linear body parameters (LBPs), average feed intake (AFI), feed conversion ratio (FCR), brooding and rearing mortalities. Comparisons between genetic groups for these parameters were done by means of analysis of variance (ANOVA) technique. Results indicated improved growth performance and feed conversion ratios in the F2 reciprocal backcross groups compared to their F2 main backcross counterparts. The F2 individuals in both crosses were superior to F1 crossbred populations. Chick mortality rates were higher in main and reciprocal backcross groups involving the naked neck genotype compared to other plumage types. It was concluded that backcrossing the F1 individuals to the exotic broiler breeder cocks increased the genetic profile of the backcross lines resulting in enhanced growth performance of progenies. Crossbreeding of exotic and local chicken varieties generated progenies that had higher genetic potentials for growth relative to the local strains and better adaptability relative to the exotic breed. However, incubation and brooding strategies capable of minimizing mortalities at embryonic, brooding and rearing phases should be explored and integrated in local chicken improvement programmes involving the use of these plumage reducing genes for optimal results.

Inheritance of Resistance to the NL-8 Strain of Bean Common Mosaic Necrosis Virus in Bean

Bean common mosaic necrosis virus (BCMNV) includes four African strains, BCMNV-NL3, -NL-5, -NL8, and -TN1, previously considered to be members of the bean common mosaic virus (BCMV) group. Many bean cultivars resistant to BCMNV-NL8 were found to be susceptible to the other strains of the virus. `California Light Red Kidney' (CLRK) and `Carbon', resistant to BCMNV-NL8, were crossed with the susceptible cultivars Sanilac or Black Turtle 2 (BT-2). In plants of F1, F2, and reciprocal backcross populations involving CLRK × `Sanilac' or BT-2 × `Carbon', the resistance to BCMVN-NL8 was determined to be conferred by a single dominant factor. The same factor was detected in BCMNV-NL8-resistant `Great Northern 1140' and `IVT-7214, when crossed with the susceptible cultivar Stringless Refugee or BT-2.

Growth patterns of first-cross and reciprocal backcross beef cows in two environments

Growth patterns of first-cross (F1) and reciprocal backcross cows, 3–5 yr old, were evaluated under two contrasting environments: extensive range conditions at Manyberries, Alberta, and semi-intensive management at Brandon, Manitoba. Cows resulting from crossing Hereford (H) × Angus (A), Simmental (S) × Shorthorn (N), Charolais (C) × Shorthorn and reciprocal backcrosses from Charolais × Hereford (CH), Charolais × Angus (CA), Charolais × Shorthorn (CN), Simmental × Hereford (SH), Simmental × Angus (SA), and Simmental × Shorthorn (SN) were evaluated at Brandon. At Manyberries, HA, SN and reciprocal backcrosses of SH, SA and SN were evaluated. All cows were bred to Limousin (L) bulls. Cow weights and backfat estimates were recorded at breeding, calving and weaning. The HA cows were the lightest group for all weigh periods at both locations. At all weigh periods, the SSN (3/4 S 1/4 N) dam crosses at Manyberries and the CCN (3/4 C 1/4 N) and CCH (3/4 C 1/4 H) at Brandon were the heaviest. At Brandon, females gained weight during gestation and usually lost weight during summer nursing. Cows at Manyberries usually gained weight during nursing, with significant gestation weight loss. Nursing status of the cow had a significant effect on weight change, with barren status providing an opportunity for large compensatory gains. The CN dams were significantly heavier at all weigh periods than their 1/4 C back-crosses. At Brandon, the SN dam cross weights exceeded those of their reciprocal backcrosses at breeding, calving and weaning and at calving for the 1/4 S dams. At Manyberries, SN weights exceeded those of the 3/4 S crosses at weaning. Over the duration of study, average backfat estimates for cows at Brandon exceeded those at Manyberries (10.8 and 8.6 mm, respectively). Specific dam crosses performed differently at the two locations, and commercial cattlemen need to closely evaluate the F1 and backcross comparisons to determine the optimal level of performance under their particular management and environmental conditions. Key words: Beef cattle, growth, nursing status, crossbreeding, environment