The suitability of 8 strawberry (Fragaria × ananassa Duch.) cultivars and selections for mechanical harvesting was evaluated by manual harvest at specified intervals during 2 ripening seasons. Single harvests 5, 8, 12 or 15 days after the date the majority of primary fruits were ripe significantly reduced marketable yields below the total yield of the conventional (several harvests throughout the ripening period) type. Highest single yields occurred on days 5 and 8. ‘WSU 1142’ produced the highest marketable yields in single harvests. These equalled 75% for day 8 in 1971 and 69% for day 5 in 1972 of the conventional harvest marketable yield. ‘Shuksan’ and ‘Hood’ also produced high single harvest yields while ‘Northwest’, ‘WSU 1165’ and ‘Rainier’ had low yields. The incidence of Botrytis fruit rot increased and mean fruit size decreased as single harvest was delayed.
Subjective capping ease ratings were used to evaluate 27 strawberry clones over a 4-year period. ‘Puget Beauty’, ‘Olympus’, ‘Totem’ and ‘Hood’ were the easiest cultivars to cap while ‘Shuksan’, ‘Rainier’ and ‘Holiday’ were the most difficult. General combining ability (GCA), specific combining ability (SCA) and GCA parent values were estimated from seedlings in 79 families. GCA parent values were positively correlated with parent phenotypic assessment (r = .828). GCA variance was 4 times larger than SCA. Heritability based on parentoffspring regression of 89 families was .84.
Pre- and postharvest fruit rot, caused by Botrytis cinerea Pers. ex. Fr., were determined during 2 seasons for 48 strawberry (Fragaria × ananassa Duch.) cultivars and selections. All had as much or more preharvest rot than ‘Totem’ which was used as the resistant standard. Many, including ‘Belrubi’, ‘Hood’, ‘Linn’, ‘Olympus’, ‘Rainier’ and ‘Sivetta’ had a significantly higher incidence of preharvest rot than ‘Totem’. ‘Totem’, ‘Olympus’, ‘Shuksan’ and ‘Rainier’ were very susceptible to postharvest fruit rot, ‘Hood’ and ‘Linn’ showed intermediate susceptibility and ‘Tago’ and several selections showed some resistance. Pre- and postharvest rot were correlated on several dates but correlation coefficients were all less than 0.585. Fruit firmness was negatively associated with both pre- and postharvest incidence of fruit rot although correlation coefficients were all less than 0.645. Many selections showing postharvest rot resistance were derived from the very firm fruited clones, NY 844 and ‘Linn’. This study demonstrates that it is possible to select firm-fruited clones which have resistance to both preharvest and postharvest Botrytis fruit rot. Clones with these three desirable traits were WSU 1522, 1641, 1647, 1675, 1696 and 1698.
Red raspberry (Rubus idaeus L.) fruit firmness, measured as compression force with a Hunter Series L portable pressure gauge, was determined from 15 parent clones and for 813 seedlings derived from 44 crosses. Heritability estimate for fruit firmness, based on parent/offspring regression, was .90 ± .13. Analysis of variance of progeny data showed that general combining ability variance (additive) was significant and much larger than specific combining ability variance. Of the parent clones, ‘Glen Isla’, ‘Glen Prosen’, SHRI6820/41, and SHRI6820/64 had the firmest fruit and, on the basis of progeny analysis, had the highest general combining ability parent values. Low parental values were obtained for ‘Sumner’, ‘Mailing Leo’, ‘Mailing Admiral’, ‘Taylor’, ‘Haida’, and ‘Meeker’.
Gibberellic acid (GA) sprays applied at 50 ppm, 10 to 30 days after planting, significantly increased runner plant production over controls (number of runner series and number of runner plants per runner series) in both greenhouse and field studies with the ‘Olympus’ strawberry (Fragaria × ananassa Duch.), a single cropping short day cultivar. GA did not influence runner plant production with ‘Northwest’, ‘Hood’, ‘Rainier’ or ‘WSU 1019’. Blossom removal significantly increased runner plant numbers with ‘Rainier’, ‘Olympus’ and ‘Hood’, but not with ‘Northwest’. Few runners were produced at late planting dates (May 18 and June 1) in an ‘Olympus’ field trial, and GA sprays 21 days after planting did not influence runner production at these late planting dates.
First-year root development on the M.7A rootstock shank was evaluated with four nonspur and seven spur-type strains of ‘Delicious’ apple (Malus domestica borkh.) The rootstock shank was the portion of the rootstock that was above the soil line in the nursery and was buried at the time of planting in the orchard. First-year total shoot length and trunk diameter increase of the scion were generally greater for nonspur than for spur-type strains. Dry weight of new roots per centimeter of rootstock shank length was correlated with shoot length and with trunk diameter increase (r = 0.53 *** and r = 0.68 ***, respectively). Although the more vigorous nonspur strains generally had more rooting on the rootstock shank than spur-type strains, there appear to be other factors, including the nursery environment, that influence shank rooting.
An orchard system is the integration of all the horticultural factors involved in establishing and maintaining a planting of fruit trees. These factors include tree density and arrangement, cultivar, root-stock and interstock, tree size and form, pruning and training techniques needed to maintain the desired configuration, mechanical training and harvesting, and support systems. An orchard system is a blueprint for the orchardist to follow throughout the life of a planting.
Calyx green end disorder (GED) of ‘Golden Delicious’ apple (Malus domestica Borkh.) is a sublethal fruit disorder characterized by a flattening distortion of the calyx lobes and a persistent green coloring of the skin at the calyx end of mature fruit. The severity of the symptom varied from mild skin greening to necrosis and was subjectively evaluated on a scale of one to 5. Fluoride applied as ammonium fluoride to spur leaves, fruit, the whole canopy, and via xylem caused symptoms identical to those in an untreated commercial orchard with a serious GED problem. Increasing severity of GED up to a rating of 3 was associated with increased levels of F in cortical calyx fruit tissue (r = 0.93). In the commercial orchard, the incidence of GED was associated with elevated levels of soil- and air-borne F. Season-long calcium chloride sprays were not effective in reducing GED, but weekly overhead irrigation rinsing treatments did significantly reduce GED severity. Gibberellins A4 + 7 (GA4 + 7) plus 6-benzylamino purine (BA) applied at bloom also reduced severity of GED but, in combination with irrigation rinsing, was no more effective than rinsing alone.
The distribution of cyanidin and pelargonidin fruit anthocyanins is presented for 37 red raspberry (Rubus idaeus L.) cultivars and selections. Nine cultivars contained 2 major fruit pigments, cyanidin 3-glucoside (Cy 3-G1) and cyanidin 3-sophoroside (Cy 3-Sop); 27 cultivars contained in addition 2 other major pigments, cyanidin 3-rutinoside (Cy 3-Ru) and cyanidin 3-glucosylrutinoside (Cy 3-G1Ru); and 1 selection ‘SHRI 6626/41’ contained in addition to the 4 pigments, cyanidin 3-sambubioside (Cy 3-Sam) and cyanidin 3-xylosylrutinoside (Cy 3-XylRu). Related pelargonidin glycosides were detected most cultivars and cyanidin 3, 5-diglucoside (Cy 3, 5-diG1) was detected in 13 cultivars.
Seedlings of strawberry (Fragaria × ananassa Duch.) from 29 crosses were evaluated in a field trial over a 2½-year period for tolerance to a complex of viruses. The seedlings and plants of the parent clones were subjectively rated for tolerance on the basis of vigor, runnering, and appearance of virus symptoms. ‘Totem’ and ‘Aiko’ produced the highest percentage of tolerant-appearing seedlings, while ‘Olympus’, ‘Belrubi’, and ‘Hood’ produced the highest percentage of susceptible seedlings. At the end of the trial, when the symptoms were most severe, heritability for tolerance was 0.73. Specific combining ability variance was much smaller than general combining ability variance, indicating that a high proportion of genetic variance was additive. Therefore, rapid progress in breeding for tolerance can be expected from selecting parent clones on the basis of phenotypic performance.