Inheritance of parthenocarpy in the cucumber (Cucumis sativus L.)

Summary The inheritance of parthenocarpy in cucumber is conditioned by an incomplete dominant gene P. In the homozygous condition PP produces parthenocarpic fruits early, with the first developing generally by the fifth node. Heterozygous Pp plants produce parthenocarpic fruits later than homozygous plants and fewer in number. The homozygous recessive pp produces no parthenocarpic fruits.Trapping of pistillate flowers was effective in identifying homozygous PP plants but failed in accurately identifying heterozygous plants. Screened cages or field isolation of gynoecious lines are efficient means of accurately identifying all parthenocarpic plants.Journal Paper No. 4333 of the Michigan Agricultural Experiment Station, East Lansing, Michigan, U.S.A.     

Toward the primary prevention of cancer

This is the threshold of an era when many of the most prevalent human cancers can, to a significant extent, be prevented through life-style changes or medical interventions. For lung cancer, the leading cause of cancer deaths in the United States, the major cause, cigarette smoking, is known and strategies for reducing smoking are slowly succeeding. Dietary changes can reduce the risk of developing large bowel cancer, the second most common cancer overall. The etiology of the major cancer in women, cancer of the breast, is sufficiently well understood that large-scale medical intervention trials are imminent. Recent changes in the incidence and mortality of these and the other major human cancers are reviewed with a brief explanation as to why these changes have occurred, followed by a summary of the state of knowledge regarding the major causes of cancer.     

Heritability of thrips resistance in the ‘IPA-3’ onion cultivar in South Texas

A two season study was conducted to compare the onion cultivars TG1015Y and IPA-3 for resistance to thrips in South Texas. Narrow and broad sense heritabilities were estimated from populations developed from the cross, ‘IPA-3’ × ‘TG1015Y’. Parents, F1, F2, and the respective backcross populations were evaluated for thrips numbers at the Texas Agricultural Experiment Station, Weslaco, TX. ‘IPA-3’ had significantly fewer thrips than ‘TG1015Y’ in both seasons. Yield was significantly different only in the 1996–97 season. The heritability of thrips resistance in this study was very low. Depending on the methods of estimation h ² was 5.3% and 4.0%, and H ² was 4.1% and 8.0%. These results suggest that greater genetic gains for thrips resistance in onion can be achieved by selection on a family basis rather than using single plant selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Systemic histiocytosis in the Bernese mountain dog

Systemic histiocytosis is a rare familial histiocytic disorder seen in the Bernese mountain dog. This article documents six confirmed cases of the disease seen at the Animal Medical Centre between June 1992 and June 1994 and describes the different presentations of the disease, response to therapy and progression. Three of the dogs are still alive; of these, two are in remission six and 18 months later and in one case the owner refused treatment. Three of the cases were euthanased for humane reasons.     

Plasma metabolites of receiving heifers and the relationship between apparent bovine respiratory disease, body weight gain, and carcass characteristics

Six hundred sixty-five crossbred beef heifers initially weighing 225 kg were used in a completely randomized design to measure plasma glucose, lactate, and urea N concentrations at time of initial processing, determine the incidence of apparent bovine respiratory disease (BRD) in receiving cattle, and evaluate the effect of apparent BRD on subsequent cattle growth and carcass characteristics. Heifers were processed within 24 h of arrival, and processing included vaccination against common viral and clostridial diseases, recording rectal temperature, and sampling whole blood for subsequent measurement of plasma glucose, lactate, and urea concentrations. Heifers were monitored for clinical signs of apparent BRD, including depression, lethargy, anorexia, coughing, rapid breathing, and nasal or ocular discharge. Heifers exhibiting signs of apparent BRD received antibiotic therapy, and the number of times a heifer was treated for apparent BRD was recorded. Following the 36-d receiving period, heifers were transported to native grass pastures and allowed to graze for 136 d. At the end of the grazing season, heifers were transported to a commercial feedlot where they were adapted to a common finishing diet offered for ad libitum consumption. Following the 124-d finishing period, heifers were slaughtered and carcass data were collected. Heifers treated for apparent BRD had decreased plasma glucose (linear, P < 0.01), lactate (linear, P < 0.01), and urea N concentrations (linear, P < 0.06) measured at time of initial processing. Rectal temperature measured at time of initial processing tended to be greater (linear, P < 0.11) for heifers treated for apparent BRD. Heifers treated for apparent BRD during the receiving period had decreased overall ADG (linear, P < 0.10), final BW (linear, P < 0.01), HCW (linear, P < 0.01), fat thickness (linear, P < 0.01), and marbling score (linear, P < 0.03). These data suggest that initial plasma glucose and lactate concentrations might be affected by the health status of receiving cattle and that increased incidence of apparent BRD in cattle decreases ADG and carcass quality.