No abstract

Efforts in grasspea (Lathyrus sativus) improvement have increased since the development of lines that are very low in the neurotoxin Beta-N-oxalyl-L-alpha-beta-diamino propionic acid (ODAP) ; also referred to as Beta-N oxalylamino-L-alanine (BOAA) . Many programs now address several related aspects of improvement simultaneously . These include reduced ODAP concentrations, insect and disease resistance, nitrogen fixation, agronomic practices, fodder and forage production, and components for increased yielding ability . The coordinated, multidisciplinary approach now being applied to the genetic improvement of grasspea should allow the potential of this largely neglected grain legume to be fully realized .

SummaryTwo studies were conducted to evaluate sulfur amino acid requirements of growing steers. In trial 1, six ruminally cannulated steers (352 lb) were used to determine methionine requirements . Treatments were abomasal infusi ons of 0, 2, 4, 6, 8, or 10 g/day of Lmethion ine. Steers were fed 5.8 lb of a soyhull and wheat straw based diet. Continuous infusion s of acetate, propionate, and butyrate into the rumen and of dextrose into the abomasum were made to increase energy. Amino acids other than methionine were infused into the abomasum to ensure that they did not limit steer performance. Nitrogen retention increased dramatically as methionine supplementation increased and, in the presence of excess cystei ne, predicted a requirement of 4 g/day of supplemental L-methionine. Plasma methionin e rose with methionine supplementatio n and predicted a supplemental methionine requirement of 2 g/day. In trial 2, five ruminally cannulated steers (429 lb) were used to det ermine how efficiently methionine is converte d to cysteine in growing cattle. The experimenta l procedures were similar to those of trial 1, except steers received a basal supplemen t of amino acids containing 4 g/day L-methionin e (requirement in the presence of excess cysteine established in trial 1) and no cysteine. Treatments consisted of abomasal infusions of 0, 1.62, or 3.25 g/day of L-cysteine or 2 or 4 g/day of additional L-methionine. Nitrogen retention was increa s ed by methionine, but not by cysteine, suggesting that cysteine could supply less than one-half of the total sulfur amino acid requirement (methionine + cysteine) of growing steers.

Tartary buckwheat (Fagopyrum tataricum) is a highly nutritious crop that is widely grown in Asia, but the Xour contains a large portion of the hull if it is ground with industrial processing since the hull is very hard to remove as it adheres to the testa layer of the groat. Rice-Tartary, a particular type of Tartary buckwheat, has seeds with a loose hull and the presence of splits on the sides of the seeds that make dehulling easily. The present study reports on the Wrst attempt of crop improvement in Tartary buckwheat breeding through hybridization. Hybrids were obtained by hybridization of crosses between Tartary buckwheat and Rice-Tartary. Additional crosses were made among selected progenies of these crosses. Based on progeny analysis of the F 1 , F 2 , and F 3 , the character of Rice-Tartary, as exhibited as the presence of splits on the sides of the seeds, is controlled by one gene which is homozygous recessive. A Tartary buckwheat breeding program has been conducted for 6 years based on these crosses. Advanced lines with easy dehull and yield potential are at the stage of ready for yield trials. Production of easy dehulling Tartary buckwheat in the future could boost Canada's domestic and international markets.

Common buckwheat (Fagopyrum esculentum) (2n = 2x = 16) and Fagopyrum homotropicum (2n = 2x = 16) were mated in an interspecific cross and amplified fragment length polymorphism (AFLP) linkage maps were constructed by analyzing segregation in the F2 population. Six hundred and sixty-nine bands were identified using 20 AFLP primer combinations, of which 462 (69%) segregated in the F2 population. The map of F. esculentum has eight linkage groups with 223 markers covering a total of 508.3 cM. The map of F. homotropicum has eight linkage groups with 211 markers covering 548.9 cM. There was one to one correspondence of the esculentum and homotropicum linkage groups. Three morphological markers, distylous self-incompatibility, shattering habit, and winged seed, were located on the AFLP map. Distylous self-incompatibility and shattering habit are tightly linked to each other (1.3 cM) and are located near the center of linkage group 1. Winged seed is located on linkage group 4.