Correlations for yield and specific gravity between potato tuberling and second year field generations

Individual hills of one 50-hill plot from each of 24 randomly chosen tuberling families were harvested in 1988 and 1989. Within each 50-hill plot, five hills were selected based on horticultural characteristics, such as shape, size, smoothness, and freedom from defects to form the population selected for horticultural characteristics (HC). From the remaining 45 hills, the five highest specific gravity hills were selected to form the population selected for specific gravity (SG). The HC and SG populations from 1988 and 1989 were planted in a randomized complete block design with two replications of six hills in 1989 and 1990, respectively. There was a significant positive correlation for yield and for specific gravity between the tuberling generation and the second year field generation in both 1988–89 and 1989–90. There was no correlation between yield and specific gravity in the second year field generation in either the SG or HC populations for 1989 and 1990. In selecting within the second year field generation on the basis of horticultural characteristics, a clone from the HC population was 1.9 and 1.7 times more likely to be selected in 1989 and 1990, respectively, than a clone from the SG population.     

Inheritance of tuber initiation in tuber bearingSolanum as influenced by photoperiod

Eight potato clones (three day-neutral (DN) Tuberosum, one dayneutral and four short-day (SD) Andigena) were used as parents. Eight genetic sets bearing P₁, P₂, P_1?, P_2?, F₁, F₂, BC₁, and BC₂ generations were developed. Two sets were DN×DN crosses, four SD×DN, and two SD×SD. Tuber initiation (TI) was evaluated in growth chambers with daylengths of 11, 13, and 15 hours. The stolons of each genotype were examined every eight days between the 38th and 86th day after planting. F₁ generation means from SD×DN crosses showed complete dominance of SD reaction (late TI) over DN reaction (early TI). F₁ generation means from DN × DN and SD× SD crosses showed either no dominance or a slight tendency towards the late TI parent. Within plot variances of the selfed generations suggested a variable degree of parental heterozygosity for the loci controlling TI. Andigena clones showed the greatest heterozygosity. Bell shaped frequency distributions in the segregating generations indicated that TI was under the control of several genes. It appears also that major and minor genes were involved. Broad sense heritability estimates of about 90% at 11 hours and 55% at 15 hours of daylength were computed.     

Recurrent selection for heat tolerance in diploid potatoes (solanum tuberosum subsp.phureja andstenotomum)

The response of diploid potatoes to growing seasons of high temperatures was studied at two locations in eastern North Carolina. The responses measured were survival, tuberization, and yield. One cycle of phenotypic recurrent selection for yield resulted in increases of 3% for survival, 15% for tuberization, and 27% for yield. Heritability of yield, estimated from selection response, was 0.07 for the combined locations. There was a small positive phenotypic correlation between the responses.     

Effects of diet on urine composition of cats with calcium oxalate urolithiasis

Ten client-owned cats with calcium oxalate (CaOx) urolithiasis were evaluated to determine the effect of diet on urine CaOx saturation. Two dietary treatments were evaluated in each cat: the diet consumed just prior to urolith detection and a canned diet formulated to prevent CaOx uroliths. This study revealed that hypercalciuria is a consistent abnormality in cats with CaOx urolith formation. When urolith-forming cats consumed a diet formulated to prevent urolith formation, activity product ratios for CaOx (which estimate the degree to which urine is saturated with CaOx) were significantly lower. These results suggest that consumption of an appropriately formulated urolith-prevention diet will reduce recurrence of CaOx urolithiasis.     

Alpha-synuclein blocks ER-Golgi traffic and Rab1 rescues neuron loss in Parkinson's models

Alpha-synuclein (alphaSyn) misfolding is associated with several devastating neurodegenerative disorders, including Parkinson's disease (PD). In yeast cells and in neurons alphaSyn accumulation is cytotoxic, but little is known about its normal function or pathobiology. The earliest defect following alphaSyn expression in yeast was a block in endoplasmic reticulum (ER)-to-Golgi vesicular trafficking. In a genomewide screen, the largest class of toxicity modifiers were proteins functioning at this same step, including the Rab guanosine triphosphatase Ypt1p, which associated with cytoplasmic alphaSyn inclusions. Elevated expression of Rab1, the mammalian YPT1 homolog, protected against alphaSyn-induced dopaminergic neuron loss in animal models of PD. Thus, synucleinopathies may result from disruptions in basic cellular functions that interface with the unique biology of particular neurons to make them especially vulnerable.