G. H. Rieman

Occurrence of hopperburn resistance and susceptibility in the potato

SummaryIn making a study of the behavior of new and old potato varieties to hopperburn injury, it has been found that, in general, the early-maturing varieties are more susceptible than the late-maturing varieties. The hopperburn tolerance exhibited by the two recently introduced varieties, Houma and Katahdin may readily account, in part, for the heat and drought resistance attributed by various investigators to these two new varieties.By selecting hopperburn-free and hopperburn-injured individuals in segregating seedling populations grown under epidemic conditions in the field, it has been possible to separate segregates into two distinct levels of hopperburn tolerance. A number of seedling cultures have been isolated which show a greater degree of resistance and of susceptibility to hopperburn than any of the new or old varieties tested.Relative percentage hopperburn resistance and susceptibility have been based on the ratio of necrotic hopperburn tissue to healthy green tissue which occurred in the various potato leaf tissues under consideration.

Superior: A new white, medium-maturing, scabresistant potato variety with high chipping quality

The Agricultural Experiment Station of the University of Wisconsin has released a new high chipping quality variety of potatoes named Superior. The new variety is a selection derived from a cross between B96-56 and M59.44 and was grown and tested under the Wisconsin advanced geneartion nmnber AG29. I t was first grown as a single hill in the field in 1951 at the University Potato Research Fa rm located near Rhinelander, Wisconsin.

Influence of planting date on potato leafhopper population and hopperburn development

ConclusionsPercentage hopperburn development was greater in the early maturing varieties than in the late maturing varieties regardless of the planting date.Percentage hopperburn development was reduced by deferring the planting date with both early and late varieties of potatoes.Nymphal leafhopper population is closely correlated with percentage hopperburn development in respect to time of planting.The results indicate that the relative earliness or lateness of a variety is not the prime factor in determining its resistance or susceptibility to hopperburn.

Diploid plants in a seedling population of the cultivated potato

The cultivated potato is a tetraploid (2n = 48). Diploid plants have heretofore been obtained following interspecific matings, using the potato as the pistillate parent and diploid tuber-bearing Solanum species as the staminate parent. When it was realized that stomatal size and number of stomata per unit area might be used as criteria for recognizing the dipliods, numerous seedlings developing from seeds produced following self-pollination between selected lines of the cultivated potato were checked. All the seedlings were more or less similar morphologically.

The resistance of the sebago variety to yellow dwarf

SummaryThe Sebago and Russet Rural varieties were compared for yellow dwarf resistance on nineteen representative farms in the yellow dwarf area of Central Wisconsin.The high field resistance of Sebago is demonstrated by the fact that only one-half of one per cent of the plants grown on the nineteen farms became infected; whereas approximately eighteen per cent of the Russet Rural plants became infected under similar conditions.The Sebago variety is not immune to yellow dwarf. Infected plants show characteristic symptoms. An avoidance of the Sebago variety by the insect vector or vectors is suggested.Yellow dwarf spread may be accurately determined in the greenhouse.The inheritability of yellow dwarf resistance is demonstrated by the low incidence of yellow dwarf in an F1 population from a cross between the resistant Sebago variety and the susceptible Hindenburg variety.

The comparative boron content of potato leaves and tubers produced under different cultural conditions

ConclusionsAnalyses of the potato tuber without corresponding leaf and stem samples give little pertinent information regarding the total ash content or the status of boron nutrition of the plant as a whole. Boron analyses of several varieties of potatoes produced in three regions of Wisconsin under similar cultural treatment have shown the following ranges and averages in micrograms per gram of dry tissue for different parts of the plants: Leaf 20.9–73.8, 38.9; stem 19.0–66.6, 32.2; and tuber 5.5–13.9, 9.2.

Potato improvement through parental line breeding—A five year report of the North Central 35 Regional Project, NC-35

SummaryThe NC-35 project has established a unified program designed to develop parents improved genetically for certain important economic characters. Researches have been conducted emphasizing concentration of genes conditioning desired characters, inheritance studies, incorporation of desired characters from IR-1 stocks, and improvement of breeding and testing methods. Though the work is difficult, progress has been made. Twenty-three publications have been reported resulting from researches relating directly or indirectly to the NC-35 project. It is anticipated that more rapid progress will be realized as the use of haploid and other new materials develop.