Development of self-incompatible Brassica napus: (II) Brassica oleracea S-allele expression in B. napus

Brassica napus var. oleifera varieties have traditionally been developed as open‐pollinated varieties. The successful introduction of several high‐yielding hybrids based on cytoplasmic male sterility or transgenic pollination control systems has generated interest in the development of new hybrid systems. Self‐incompatibility could be an additional useful pollination control system for B. napus if a sufficient number of S‐alleles could be developed in this species. The S‐alleles, S2, S5, S13, S24 and S39, were identified in five hybrids of B. oleracea var. italica and subsequently transferred to B. napus. Doubled haploid lines were produced for the self‐incompatible (SI) lines in B. napus and intercrossed to produce SI heterozygotes in order to study allele interaction. There was a greater incidence of interallelic dominance in the stigmas and pollen of B. napus than was reported for the S‐alleles in B. oleracea. Allele S24 exhibited the greatest degree of dominance over the other alleles tested, while allele S2 was generally recessive or codominant with other alleles. Self‐incompatible expression was very similar in the SI homozygotes and heterozygotes, thus no weakening of the SI trait in the heterozygote was observed. The implications of S‐allele interaction for the use of SI in B. napus are discussed.     

Foliar pesticide residues in relation to worker re-entry

Residues were determined at 8-h intervals during the 48 h after application of endosulfan, leptophos, methamidophos, methomyl and mevinphos to head lettuce; of endosulfan, methamidophos and methomyl to cauliflower; and of parathion to onions and carrots. Residues of phosalone and parathion were measured on apple leaves 0, 1, 2, 4, 8 and 16 days after application. In addition, the portion of the residue on apple leaves that could be dislodged was measured, as well as the residues on gloves used to handle the apple foliage. There were large differences in the rates of disappearance of the insecticides, differences that must be known in determining safe re-entry periods for workers.     

Effect of Competition on Nitric Oxide, Carbon Monoxide, and Cyclic Guanosine Monophosphate Levels in Training Horses

The aim of this study was to compare the effect of exercise on nitric oxide (NO), carbon monoxide (CO), and cyclic guanosyl monophosphate (cGMP) levels in jumping and dressage horses involved in competition. Blood samples were collected from the jugular vein of 100 horses involved in jumping or dressage competition at three time points: baseline at rest, on reaching the schooling but before exercise, and over a jump or dressage course. Fourteen healthy horses not involved in competition were used as control group. Exercise increased plasma CO concentration in both jumping and dressage horses, and this effect was more apparent in dressage horses. Exercise also increased NO plasma concentration in jumping horses, whereas it did not significantly modify NO plasma concentration in dressage horses. After exercise, plasma cGMP concentration was higher in both groups. Our results show that different signaling pathways are initially activated by exercise and that this activation is specific to the different modes of exercise. This information can be used to optimize warm-up and cool-down procedures for sport horses or to optimize training programs for equine athletes.