QUANTITATIVE GENETIC EVALUATION OF GROWTH TRAITS, HETEROSIS AND RECIPROCAL EFFECTS IN THREE BREEDS OF DOMESTIC TURKEYS IN NASARAWA STATE, NIGERIA

Abstract

The quantitative genetic effects of the growth traits of the Domestic Turkey (Meleagric gallapavo) in Lafia, Nasarawa State, North Central Nigeria was evaluated using a total of 200 day-old poults. A full diallel crossing experiment was conducted using three phenotypes of indigenous domestic turkeys with the following plumage colour: black, white and lavender (spotted). The poults used for the study were hatched from a foundation stock of 60 Turkeys comprising 15 Hens and 5 Toms for black, white and lavender phenotype. Mating ratio of 1 male: 5 females were employed. Randomized complete block design (RCBD) was also used to analyze the data with phenotypic class as a major factor and batch as block. Data obtained were subjected to analysis of variance (ANOVA). Results obtained showed that body weight (BW) and Linear body traits (body length, wing length, drumstick length, breast width, shank length, keel length and neck length) had a significant increase as age (weeks) increased for the main (direct) crossbred (black x lavender (spotted), BxS) and Lavender x Black compared with its purebred (Black x Black, (BxB), White x White (WxW) and lavender x lavender (SxS) counterparts. There were non-significant (P>0.05) differences in initial body weight of the purebred (31.04, 31.35 and 31.53g), main crossbred (34.86, 34.96, 35.06g) and reciprocal crossbreds (35.02, 35.26 and 35.68g), respectively, whereas final body weights for main crossbred (3710.25, 3732.42 and 3738.66g) and reciprocal crossbred (3791.58, 3795.72 and 3797.44g) differed significantly (P<0.05) across the weeks. There were also significant (P<0.05) differences in average daily weight gain (g/day) among the F1 main and reciprocal crossbreds (336.67, 338.08 and 339.55g), (329.61, 338.08 and 339.55g) compared to their purebred (322.33, 323.55 and 323.38g) counterparts. The significant (P<0.05) difference observed in BW and LBM (BL, WL, BRW, DS, SL, KL and NL) values ranged from 2493.1 to 3320g, 37.50 to 40.26cm, 31.43 to 34.29cm, 28.04 to 30.96cm, 18.95 to 20.24cm, 13.05 to 15.05 cm, 13.81 to 14.06 cm and 17.05 to 17.67 cm, respectively for BW and LBMs. Positive heterosis (hybrid vigour) was observed for BW and all LBMs measured in the main (direct) (BxW, BxS, and WxS) and reciprocal crossbreds (WxB, SxB and SxW) studied, ranging from 0.12 to 0.83,11.35% to 33.64%, 0.56 to 2.70, 1.88% to 8.26%, 0.96 to 2.99, 7.51% to 30.88%, 0.48 to 1.18, 4.32% to 13.59%, 0.65 to 8.96, 1.10% to 8.96%, 0.43 to 4.05, 1.67% to 39.89%, 1.31 to 2.49, 7.76% to 14.62% and 0.50 to 2.41, 2.93% to 34.16%, respectively for BW, BL, WL, BRW, DS, SL, RL, and NL. There were positive and significant correlations in weeks 14 and 16 between the growth traits measured. It is concluded that the significance (P<0.05) differences observed for most LBMs and BW in different ages (weeks) for indicates that non-additive effects of genes could be exploited through crossbreeding of BxS, BxW and WxS genotypes to bring about genetic improvement for BW and LBMs. Thus, positive and significant phenotypic relationship between linear body parameters and body weight indicates that an improvement in one trait could lead to a concomitant improvement in others, if environmental factors are negligible.