Postpartum dam performance was studied in a complete diallel design involving five lines of mice. The selection criterion in each line was: large litter size at birth (L+); large 6-wk body weight (W+); an index for large litter size and small 6-wk body weight (L+W-); the complementary index (L-W+) and random (K). Females from the five lines and 20 reciprocal F1 crosses were mated to sires of a ...

INCE the pioneering work of CHETVERIKOV ( 1927), many studies have shown that a large number of phenotypically normal individuals in natural populations of outbred diploid species, such as Drosophila, carry numerous recessive lethal genes concealed in heterozygous condition. The experiments of STERN, CARSON, KINST, NOVITSKY and UPHOFF (1952), MULLER and CAMPBELL (see MORTON, CROW and MULLER 195...

Using native trees from near the northern and southern extremities of the relatively continuous eastern distribution of Eucalyptus globulus in Tasmania, we compared the progenies derived from natural open-pollination (OP) with those generated from within-region and long-distance outcrossing. Controlled outcrossing amongst eight parents - with four parents from each of the northern and southern ...

A crossbreeding experiment was carried out between two Egyptian strains of chickens namely Mandarah (MM) and ElSalam (SS). The two purebred strains and their reciprocal crosses (MS and SM) were used to estimate the effect of crossing on egg laying and egg quality parameters, direct additive and maternal additive effects as well as heterosis and direct heterosis percentages for studied traits. R...

Results from a 10-yr study of five dam breed groups in a range beef production system were used as inputs to a simulation model to evaluate life cycle biological and economic performance. Dam breed groups were straightbred Herefords (HH), Angus-Hereford and Simmental-Hereford F1 crosses (AH and 1S1H), 75% Hereford-25% Simmental (1S3H), and 25% Hereford-75%. Simmental (3S1H). Biological measures...

The present investigation has been undertaken in sweet corn to carry out the combining ability analysis and to estimate heterosis of yield and yield contributing characters. Eight divergent parents were selected and crossed in diallel fashion excluding reciprocals during kharif, 2010. The resulting 28 crosses along with parents and a standard check Sugar 75 and Madhuri were evaluated in Randomi...

N MOST parts of the geographic distribution of Drosophila psezcdoobscura, I chromosomal types which differ in gene arrangement in the third, the X, and, less frequently, in other chromosomes occur in the populations. The diversity of the gene orders is due to inversion of chromosome sections. Since the chromosomal types interbreed a t random, inversion heterozygotes and homozygotes are found in...

a study was conducted on genetics of some important agronomic traits (number of productive tillers per hill, plant height (cm), panicle length (cm), number of spikelets per panicle and 100-grain weight) in rice during 2012-13. two lines were crossed with five testers in line × tester fashion to produce 10 f1 hybrids. analysis of variance revealed significant differences among genotypes and cros...

combining ability effects were estimated for different agronomic characters in line × tester crossing program comprising 21 hybrids produced by crossing 7 lines and 3 testers. parents and hybrids differed significantly for general combining ability (gca) and specific combining ability (sca) effects, respectively. the variance due to gca and sca showed that gene action was predominantly additive...

ETEROSIS in characteristics which are part of the reproductive process is a commonly observed result of crossing unrelated stocks in many species (e.g., GOWEN 1952). In mammals, the observed heterosis in litter size could be due to superiority of the crossbred in ovulation rate, in embryo survival, or both. The second of these parameters can be further subdivided into preand postimplantation st...