Search Results
Abstract
Shoot invigoration and rooting potential of hard-to-root ‘46-1 Mazzard’ sweet cherry (Prunus avium L) was progressively increased during six consecutive subcultures when cocultured with easy-to-root ‘Colt’ (P. avium × P. pseudocerasus). Similar results were produced with gibberellic acid at a concentration range of 0.1 to 0.25 mg·liter−1, but rooting depended on transfer to a GA3-free medium. It is suggested that the invigoration and enhanced rooting involved rejuvenation of the mature ‘46-1 Mazzard’ to a more juvenile phase.
Abstract
Investigation of pollen grain germination and retention on the stigma, and pollen tube frequency in the style following compatible (cross) and incompatible (self) pollinations in ‘Nonpareil’ almond [Prunus dulcis (Mill.) D.A. Webb Syn. Prunus amygdalus Batsch.J revealed that rejection of incompatible male gametophytes occurs on the stigma as well as in the style. Self-pollinations are characterized by lower pollen grain retention on the stigma, reduced and delayed pollen germination, and, where pollen germination had occurred, a low frequency of pollen tubes growing through the style. Pollen tube growth slowed greatly after the tubes entered the ovarian locule before they reached the ovule.
Abstract
Harvesting seed of ‘Manzanillo’ olive (oleo europaea L.) at the end of October, when embryo growth was complete, gave optimum germination and extended storage life with lower germination rates and shorter storage life before or after this date. Optimum germination occurred at 15°C for whole seed and 25° for excised embryos; both grew faster at 25° after germination. Seed and excised embryos germinated equally well in light or dark.
Abstract
Three new cultivars of almond [Prunus dulcis (Mill) D.A. Webb syn. P. amygdalus Batch] are released for distribution. ‘Solano’ has a high-quality kernel and could be grown in combination with ‘Nonpareil’ for simultaneous bloom and sequential harvest. ‘Sonora’ has a high-quality kernel, blooms earlier than ‘Nonpareil’, and could be used as a substitute for or in combination with ‘Ne Plus Ultra’ and ‘Peerless’. ‘Padre’ is a high-yielding, late-blooming cultivar that could be planted together with or as a substitute for the ‘Mission’.
Abstract
Leaf resistance (r1) in fully exposed leaves of bud-failure (BF) sensitive subclones of 2 almond (Prunus amygdalus Batsch) cultivars was much greater than in leaves of non-BF-sensitive (normal) subclones of these cultivars. The differences in resistance were evident at ambient temperatures between 26° and 38°C, and temperatures of fully exposed leaves on BF-sensitive plants exceeded ambient temperature and averaged 5° higher than leaf temperature of normal plants. The difference between BF-sensitive and normal subclones was not apparent below 25° or above 39°. Increase in resistance preceded the development of abnormal growth patterns characteristic of the BF syndrome, and these differences may serve to identify BF sensitivity at incipient stages of the syndrome. Stress is accentuated in BF-sensitive clones between 26° and 38° because transpirational cooling is suppressed; however, the physio-chemical basis of BF sensitivity remains obscure.
Abstract
Exposure of growing shoots to high temperature resulted in symptom expression of noninfectious bud-failure, a “genetic disorder” in almond Prunus amygdalus Batsch, whereas lower temperature prevented expression. Exposure of the normal phase of the disorder to high temperature gradually induced symptom expression.
Abstract
Establishment, shoot proliferation, root induction, and transplanting stages were accomplished with Prunus avium × P. cerasus cv ‘Colt’, ‘Dwarf Mahaleb’ (P. mahaleb L) (both vegetatively propagated rootstock cultivars) and seedling Mazzard sweet cherry (P. avium L) ‘46-1 Mazzard’, (P. avium L.), a clonal rootstock seed tree, could be established and multiplied by the same procedure. However, no rooting was obtained. Limited rooting was possible with seedling Mazzard trees < 3 years in age. It was concluded that the limiting factor in ‘46-1 Mazzard’ rooting was the mature status of the source material.
Abstract
Easy-to-root ‘Colt’ showed cell divisions leading to root initials beginning within 2 days after exposure to auxin. By contrast, juvenile (i.e., 2-year-old seedling) rooting Mazzard (P. avium) and invigorated (i.e., by co-culture) rooting ‘46-1 Mazzard’ required 4 and 5 days. Root initials appeared in the phloem parenchyma in ‘Colt’ and in the cambium region in both seedling Mazzard and invigorated ‘46-1 Mazzard’. Peroxidase activity (PA) was low in shoot tips of ‘Colt’, intermediate in juvenile Mazzard, and high in adult non-rooting ‘46-1 Mazzard’. In basal shoot tissue, PA activity was low in both ‘Colt’ and invigorated ‘46-1 Mazzard’ prior to root initiation, but increased sharply when root initiation started. The appearance of root initials was associated with an increase in intensity of anodic band A for isoperoxidase.
Abstract
Horizontal starch gel electrophoresis was used to study the inheritance of some isozyme variants in almond seedling and almond-peach hybrid populations. In almond, aspartate aminotransferase (AAT), glucose phosphate isomerase (GPI), and leucine aminopeptidase (LAP) have two zones of activity, one of which is monomorphic in each case. The polymorphic loci, AAT-1 and GPI-2 each had two alleles and behaved as dimers in the electrophoretic analysis. LAP-1 behaved like a monomeric enzyme with two functional alleles, in addition to an hypothesized null allele. PGM behaved like a monomeric enzyme specified by two polymorphic loci, Pgm-1 and Pgm-2. Pgm-1 displayed two alleles, while Pgm-2 apparently had three, although one gave aberrant segregation ratios. Acid phosphatase (AcP), glyceraldehyde-phosphatase dehydrogenase (GAP), and 6-phosphogluconate dehydrogenase (6-PGD) isozymes showed two zones of activity in the almond cultivars assayed and produced no allelic variation. In peach, AAT-1 and GPI-2 had the same Rf values as almond and segregated in typical Mendelian ratios in F1 and F2 almond × peach populations. The alleles for LAP-1 and LAP-2 not only had different mobilities in almond and peach but were tightly linked to each other within each species. Thus, four-banded patterns were produced in the F1, which segregated in the F2 to peach, almond, and hybrid phenotypes with a reduced number of recombinants.
Abstract
Relationships among blooming and leafing dates of parents, offspring, and the chilling requirements of the intervening seed were determined among a group of families of almond (Prunus amygdalus Batsch). Parentoffspring heritabilities for blooming and leafing dates were high. Leafing and blooming dates of individuals and families, although significantly correlated, were more or less independent traits. Seed chilling was a function of both seed and pollen parents and was correlated with mean bloom and leafing of parents. The correlation coefficient between chilling of a seed and the blooming date of the corresponding offspring plant was significant and large when calculated for families and significant, but low, when calculated for individuals. The seed-leafing correlation was significant when the early and late leafing progeny were considered separately.