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Legnaro, Italy

Mazza S.,Agripolis | Mantovani R.,Agripolis
Acta Agriculturae Slovenica

The aim of the study was to estimate heritabilities (h2) of type traits and linear description scores in Rendena breed. Five traditional summary traits and 20 linear descriptions were recorded on 9,776 Rendena primiparous cows. All available pedigree information (16,234 animals) was used to set up the relationship matrix among animals. Data were analyzed using a single-trait animal model, accounting for the following effects: herd-year-classifier, days in milk, age at first calving, and the genetic additive cow effect. The most heritable trait was the stature (h2 = 0.53), whereas the lowest value was found for feet (0.13). Other considerable values of heritability were found for body size (0.45), body length (0.40), and udder width (0.43). Medium-high heritability estimates were obtained for fleshiness (0.33), and udder (0.35), and regarding linear description for thigh-buttocks traits (0.32, and 0.33), thinness and rump angle (0.36 for both traits), as well as teat length (0.33). On the other hand suspensory ligament (0.17), and thorax length (0.16) showed low heritability values. However, the general good heritability estimates suggest the possibility to use linear description or type traits in genetic evaluation of Rendena cattle. Source

Assefa T.,Melkassa Agricultural Research Center | Beebe S.E.,Centro Internacional Of Agricultura Tropical Ciat | Rao I.M.,Centro Internacional Of Agricultura Tropical Ciat | Cuasquer J.B.,Centro Internacional Of Agricultura Tropical Ciat | And 4 more authors.
Field Crops Research

Common bean (Phaseolus vulgaris L.) is an important food legume grown in Africa and Latin America, where water deficits frequently reduce grain yield. The objectives of this study were to identify advanced lines of common bean with superior seed yield under drought, and to identify plant traits that could serve as selection criteria for evaluating drought resistance. Seventy-eight advanced inbred lines (genotypes) were generated by single seed descent and evaluated with the two parents (ICA Bunsi, a white pea bean variety and SXB 405, a breeding line) and a standard check (Awash melka) under drought and irrigated field conditions in 2008 and 2009 at Melkassa, Ethiopia. Seed yield, seed number per m2, pod number per m2 and 100 seed weight were reduced by 65%, 34%, 29% and 12%, respectively under drought stress compared to irrigated conditions. Two genotypes (G87, G80) had better drought yield compared with a standard check, and several also responded to irrigation. Pod harvest index (PHI; [dry weight of seed/dry weight of pod at harvest]×100) was reduced in sensitive genotypes and increased in resistant genotypes under drought stress conditions indicating the importance of remobilization of photosynthates from pod wall to seed. Principal component analysis indicated that the first component including five traits (grain yield, seed number per m2, pod number per m2, 100 seed weight and PHI) explained 35.7% of the total variation under drought stress. Correlations of PHI with yield (0.43***) and fair heritability (0.48) in drought suggest that PHI would be an effective selection criterion for identifying genotypes with improved drought resistance. Correlated gain in drought yield from selection for PHI would be greater than direct yield selection, due to much better heritability of PHI, and would also contribute to irrigated yield. © 2013 Elsevier B.V. Source

Mazza S.,Agripolis | Guzzo N.,Agripolis | Sartori C.,Agripolis | Berry D.P.,Teagasc | Mantovani R.,Agripolis
Journal of Animal Breeding and Genetics

The aim of the study was to estimate the genetic parameters for five composite traits and 20 individual type traits on 10 735 first-parity Rendena dual-purpose cows. Fixed effects included in the linear animal mixed models were herd-year-classifier, days in milk and age at first calving; the additive genetic effect of the animal was included as a random effect. Heritability estimates varied from 0.12 (feet) to 0.52 (stature). Genetic correlations between the individual body size traits were all ≥0.69; similar strong genetic correlations existed between traits describing similar morphological characteristics (e.g. mammary system, fleshiness). Many of the body size traits were negatively genetically correlated with animal fleshiness. Genetic trends showed that genetic merit for body size increased consistently over the last 10 years, while genetic merit for fleshiness declined. These results suggest that the characteristics of the dual-purpose Rendena cattle are becoming more like specialized milk-producing animals. Nonetheless, sufficient genetic variation exists to halt or reverse the deterioration in fleshiness. © 2013 Blackwell Verlag GmbH. Source

Mantovani R.,Agripolis | Cassandro M.,Agripolis | Contiero B.,Agripolis | Albera A.,Associazione Nazionale Allevatori Bovini di Razza Piemontese | Bittante G.,Agripolis
Journal of Animal Science

The aim of this study was to estimate genetic parameters for type traits of hypertrophic Piemontese cows. Seven traditional type trait evaluations (70 to 100 grid scores), 2 body measurements (cm), and 13 linear description traits (1 to 9 grid scores) recorded on 21,757 Piemontese primiparous cows reared in 990 farms were used. Data were analyzed using a multiple-trait (22 traits) animal model with canonical transformation, accounting for a unique design matrix with the following effects: herd-year-classifier, days in milk, age at calving, and the genetic additive cow effect. Heritability estimates of traditional type evaluation traits were low for thorax, rump, feet and legs, and dairyness (≤0.10), intermediate for fleshiness and overall score evaluations (0.13 to 0.15), and medium to high for body size (0.26). Genetic correlations of dairyness with all the other traditional type traits were low (from -0.14 to 0.16), those of feet and legs were moderate (0.19 to 0.44), and the remaining 5 traits were high (≥0.55), with an exception regarding fleshiness and body size (0.28). Medium-high heritability estimates were obtained for withers height (0.31) and trunk length (0.21), with a very high genetic correlation between these traits (0.97). The genetic correlations of body measurements with body size were also very high (about 0.96), high with thorax, rump, and overall score (0.47 to 0.59), and moderate with the other traditional type traits (0.04 to 0.27). Heritability estimates of all linear traits were moderate (0.09 to 0.15), with the exceptions of top line (0.07) and condition score (0.05). Genetic correlations between linear traits were generally low to moderate (from -0.11 to 0.44) with the only exceptions of the 6 fleshiness traits and body condition, which showed very high correlations (0.60 to 0.96). Moreover, skeletal traits as top line, bone thinness, and head scores presented moderate genetic correlations (0.51 to 0.65). Genetic correlations between linear traits and traditional type traits were consistent with the trend observed between type traits. In conclusion, body measurements seem to describe body size better than traditional evaluation or linear descriptors. The genetic correlations among type evaluation and linear description traits suggest the need for a reduction in the number of traits scored, particularly of those relating to muscular development. © 2010 American Society of Animal Science. Source

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