The genealogy of an inbred poland china herd of swine

This archival publication may not reflect current scientific knowledge or recommendations

Effects of burial, stem portion and cultivar on the decomposition of canola straw

Buried canola straw underwent 1.6 to 2 times as much decomposition as straw on the soil surface. Decomposition of Brassica napus L. was slightly less than that of B. rapa L. and cultivar effects were small in one year and insignificant in the other. Because treatment effects varied between stems and roots, plant portion likely should be considered in decomposition studies. Key words: canola, straw decomposition, burial, cultivars </jats:p

INFLUENCE OF BODY WEIGHT AND CHANGES IN BODY WEIGHT OF THE COW ON PREWEANING TRAITS OF THE CALF

This study was designed to estimate and evaluate environmental factors affecting birth weight, weaning weight and preweaning average daily gain (ADG) of purebred Shorthorn calves from the control line of a selection experiment. Nine years of data consisted of 635 birth weight and 607 weaning weight records. Least squares analysis of variance revealed that sex of the calf was the most important source of variation: males averages 2.31 kg heavier at birth, were 14.3 kg heavier at weaning and gained 0.08 kg more per day from birth to weaning than females. Heavier cows in June, October, and December prior to parturition and at parturition produced heavier calves at birth. Heavier cows in October prior to parturition, at parturition, and in June or October following parturition produced calves which grew more rapidly from birth to weaning and were heavier at weaning. There was no apparent effect of cow weight changes before or after parturition on preweaning traits. Correlations of birth weight with weaning weight, preweaning ADG and cow weight at parturition were 0.56 ± 0.03, 0.43 ± 0.04 and 0.24 ± 0.04 respectively. Correlations of weaning weight and preweaning average daily gain with cow weights at parturition were 0.42 ± 0.04 and 0.40 ± 0.04. Correlations among cow weights in June, October, and December prior to parturition, at parturition, and in June and October following parturition were estimated. </jats:p

CYTOGENETIC ANALYSIS OF CHROMOSOMAL TRANSLOCATIONS IN THE TOMATO: PREFERENTIAL BREAKAGE IN HETEROCHROMATIN

A tester set of eight translocations has been selected involving all 12 chromosomes of tomato (Lycopersicon esculentum Mill.). Using the entire tester set, seven other translocations were identified. Five others were identified, using information from crosses with certain of the testers and with additional translocations. Three lines are homozygous for two translocations (2 04 in the heterozygotes). There are several instances in which more than one stock involves the same two chromosomes. Cytological analyses of tomato translocations show that breakages that give rise to translocation chromosomes occur more frequently in centromeric and heterochromatic regions than in euchromatic and are not distributed according to pachytene chromosome length. A list of available tomato translocations with information on mode of production, source, and breakpoints is included.</jats:p