Search Results
Abstract
During the first 5 years of production, significantly greater yields of pistachios were obtained with the ‘Kerman’ on seedlings identified as Pistacia atlantica Desf. than with ‘Kerman’ on seedlings of P. palaestina Boiss., P. terebinthus L., or P. vera L. The least productive combination was ‘Kerman’ on P. vera, the species that produces the edible pistachio nut. Weight per nut, percent blank nuts, and percent nuts with split shells did not differ significantly among the rootstock combinations.
Abstract
Data on 15 traits collected from 30 walnut selections were analyzed for changes in relation to both clone and rootstock age. Data collection began at first flowering (age 3 or 4) and continued annually for up to 28 years on each clone. Significant correlations were found between seasonal timing of the expression of phenological traits and clone age. The general trend was towards earlier leafing, bloom, and time of nut maturity as the clone aged. Correlations with rootstock age were lower than with clone age for phenological traits. Shell and kernel trait expression was more highly correlated with rootstock age than clone age, suggesting that changes may be due to vigor and other effects of grafting rather than aging per se. Estimates of the age of stabilization for phenological traits ranged between 9 and 18 years from germination. It is suggested that changes in leafing, bloom, and nut maturity dates be considered prior to commercial release of walnut cultivars.
Abstract
In a 16-year field study, all graft combinations of Persian walnut, Juglans regia scions with other rootstock species were susceptible to blackline. ‘Sinensis #5’, a selection of J. regia, did not exhibit symptoms of blackline when used as an interstock. In no case was blackline observed in graft combinations between J. regia.
Abstract
Walnut trees planted at 50’ × 30’ grew more slowly than xtrees at 50’ × 40’ or 50’ × 50’. Yields per tree were similar at all spacings early in the orchard’s life, but unit area yields later increased proportionately to the number of trees per acre. Long-term monetary returns above fixed costs were far greater as the number of trees per acre increased.
Abstract
Kernels from Juglans regia walnuts stratified at 0°C were sampled at weekly intervals and extracted with methanol. The extracts were partitioned into 4 phases which were water, neutral ether, acidic ether and acidic butanol, then bioassayed for cytokinins, gibberellins, auxins and inhibitors. No cytokinins nor gibberellins were found in the tissue. There was activity analogous to that from auxins. An inhibitor which diminished during stratification was found. This inhibitor is believed to be abscisic acid, on the basis of UV absorption spectrum, Rf values established by co-chromatography on paper and silica gel plates, and derivatives analyzed by gas liquid chromatography.
Abstract
Viability of walnut, Juglans regia L., pollen was not diminished by storage at subfreezing temperature, as previously indicated. Pollen stored 20 days at −19°C effected high percentages of fruit set in the orchard in 1969. Fruit set of the bagged flowers was relatively low in 1970, but the set effected by pollen stored a year at −19°C was not significantly different from that effected by fresh pollen. Laboratory tests indicated less than 1% germination for both freshly dehisced and stored pollen, and were unreliable for indicating the ability of walnut pollen to effect fertilization.