The heritability of resistance to root-knot nematode (Meloidogyne incognita acrita CHIT.) in Vitis vinifera x V. rotundifolia hybrid derivatives

A population of 807 offspring of 46 families, generated by crosses among 26 parents (some quasi-F1 hybrids of V. vinifera x V. rotundifolia), the parents, 12 V. vinifera x V. rotundifolia (VR) hybrids, Muscat of Alexandria and Dog Ridge (controls) were all grown in the vineyard of the University of California at Davis and were tested in a greenhouse for resistance to the sedentary endoparasite root-knot nematode (Meloidogyne incognita acrita CHIT.). Some of the seedlings and parents and almost all the VR hybrids showed resistance to the nematode and ratings were verified by retesting. The heritability was estimated tobe 0.391 ± 0.06. The expected average gain of the progeny of randomly mated parents ranked in the upper 5 % of the parental generation were calculated. The result indicates that relatively rapid genetic gain is to be expected in the population based on their own performance and subsequent mating, inter se, without use of the more expensive methods of progeny testing and inbreeding which are used to exploit non-additive portions of the genetic variability.The uses of the resistant plants as rootstocks and the langer term combination with desirable economic characters are discussed.Die Heritabilität der Resistenz gegen Wurzelgallennematoden (Meloidogyne incognita acrita CHIT.) bei Vitis-vinifera x V.-rotundifolia-KreuzungsnachkommenEine Population von 807 Nachkommen aus 46 Familien, die aus Kreuzungen zwischen 26 Eltern (Quasi-F1-Kreuzungen aus Vitis vinifera und V. rotundifolia) hervorgegangen sind, die Eltern selbst, 12 V.-vinifera x V.-rotundifolia-Kreuzungen (VR) sowie Muskat von Alexandria und Dogridge als Kontrollen wurden in einer Rebanlage der Universität von Kalifornien, Davis, herangezogen und im Gewächshaus auf ihre Resistenz gegen das endoparasitische Wurzelgallenälchen Meloidogyne incognita acrita CHIT. geprüft. Verschiedene Sämlinge und Eltern sowie fast alle VR-Kreuzungen zeigten Nematodenresistenz; die Ergebnisse wurden durch eine zweite Resistenzprüfung bestätigt.Die Heritabilität wurde auf 0,391 ± 0,06 geschätzt. Die durchschnittlich zu erwartende Verbesserung der Resistenz in der Nachkommenschaft aus zufällig gekreuzten Eltern, die unter den oberen 5 % ihrer Generation rangierten, wurde errechnet. Das Ergebnis zeigt, daß eine relativ rasche genetische Verbesserung erwartet werden kann, wenn sich die Reben einer leistungsfähigen Population zufällig untereinander kreuzen können. Aufwendigere Methoden der Sämlingsprüfung und der Inzucht, durch welche üblicherweise die nichtadditiven Anteile der genetischen Variabilität ausgenützt werden, erübrigen sich dann.Die Verwendung der resistenten Reben als Unterlagen und, längerfristig, zur Kombination von Resistenz und wünschenswerten Eigenschaften der Trauben werden diskutiert

Cytogenetics of Vitis III. Partially fertile F1 diploid hybrids between V. vinifera L. x V. rotundifolia MICHX.

An unusual, partially-fertile population of diploid Vitis vinifera x V. rotundifolia F1 hybrids is described. These hybrids are partially fertile with varieties of both parental species.It is suggested that the success of hybridization, as measured by the fertility of the F1 hybrids, depends on the V. vinifera clone originally used as a female parent.In meiosis of these F1 plants, average bivalent formation varies from 13.1 to 15.6 per cell at MI. There is a correlation in the diploid VR hybrids between chromosomal pairing at MI and fertility of the vines.Some V. rotundifolia characters are dominant in diploid F1 hybrids.In regard to crossability, the F1 hybrids are reciprocally crossable with V. vinifera varieties, but can only serve as female parents with V. rotundifolia. Evidence from breeding tests indicates that incompatibility between V. rotundifolia x V. vinifera is not due to cytoplasmic inheritance, but is caused by nuclear factors

Cytogenetics of Vitis IV: Backcross derivatives of V. vinifera L. x V. rotundifolia MICHX.

Diploid ibackcross :progeny of (V. vinifera L. x V. rotundifolia MICHX.) x V. vinifera L. were studied in the present investigation.In the diploid backcross (BC1) progeny a range from completely sterile seedlings to others as fertile as standard V. vinifera varietes was obtained.Average bivalent formation at MI in the diploid BC1 progeny varied from 7.9 to 16.1. There was a relation in BC1 hyibrids between chromosomal pairing at MI and fertility of the seedlings.BC1 seedlings ,segregated for some V. rotundifolia characters (fruit quality, flavor, type of bark, tendrils, diaphragm, size of flower clusters, shape of the leaves, etc.). Wood type was the only characteristic of V. rotundifolia. which was found in all BC1 seedlings.Crossability pattern of the BC1 progeny to V. vinifera and V. rotundifolia was the same as that of F1 VR hybrids; namely, only as a female parent to V. rotundifolia and female or male to V. vinifera

Resistance to grape phylloxera in Vitis vinifera x V. rotundifolia grape hybrids

A population of 278 offspring generated by crosses among 26 parents (some quasi F1 hybrids of Vitis vinifera x V. rotundifolia), some of the parents, 3 V. vinifera x V. rotundifolia hybrids (VR), Muscat of Alexandria (susceptible control), and V. rupestris du Lot (St. George) (resistant control), all grown in the vineyard of the University of California at Davis, were tested in a greenhouse for resistance to the grape phylloxera, Phylloxera vitifoliae FITCH. Some of the seedlings, a parent, and the 3 VR hybrids showed resistance to the pest and verified by retesting. The uses of the resistant plants as rootstocks or in a vine breeding project are discussed.Die Reblausresistenz von Vitis-vinifera x V.-rotundifolia-KreuzungenEine Population von 278 Nachkommen aus Kreuzungen zwischen 26 Elternreben (Quasi-F1-Bastarde aus Vitis vinifera x V. rotundifolia), etliche dieser Eltern, 3 V.- vinifera x V.-rotundifolia-Kreuzungen (VR), Muskat von Alexandria als anfällige Kontrolle sowie V. rupestris du Lot (St. George) als resistente Kontrolle - sämtliche Reben aus einer Anlage der Universität von Kalifornien, Davis - wurden im Gewächshaus auf die Resistenz ihrer Wurzeln gegen die Reblaus geprüft. Einige der Sämlinge, 1 Elternrebe und die 3 VR-Kreuzungen erwiesen sich, auch bei einer zweiten Prüfung, als reblausresistent. Die Verwendung der resistenten Reben als Unterlagen oder zur Züchtung von Ertragsreben wird diskutiert

Heritability and correlation studies of certain quantitative traits in table grapes, Vitis spp.

Heritabilities and phenotypic correlations among 10 traits of the grapevine (Vitis vinifera x V. rotundifolia hybrid derivatives) were estimated from measurements obtained from 46 families, induding a total of more than 1000 offspring generated by crosses among 26 parents. Measurements on fruit characters were obtained over a period of 4 years, 1976-1979. (General vigor of the vines was measured in only 1 year, 1976). Prior to this analysis the data on fruit traits were statistically adjusted to mitigate the confounding effects of fluctuating annual dimates on estimates of genotypic value. The heritabilities were then estimated by regressing the average performance of each seedling on the average performance of its mid-parent. Heritabilities are 0.12, 0.55, 0.49, 0.75, 1.04, 0.34, 0.15 and 0.10 for duster weight, duster compactness, berry weight, skin texture, pulp texture, total soluble solids, acidity of juice and general vigor, respectively. The heritability estimate for crop weight in this population is practically 0(-0.08). The precision of these estimates is very high, except for that of general vigor. Thus, they should be reliable predictors of the rate of genetic gain attainable in such populations when seedlings are selected as parents on the basis of their own performance. The expected performance of the progeny of randomly mated parents, ranked in the upper 5 % of the progeny generation, were estimated. The implications of these genetic relationships on the effectiveness and efficiency of breeding programs and selection procedures in grapes are discussed

Cytogenetics of Vitis V. Allotetraploids of V. vinifera L. x V. rotundifolia MICHX.

The allotetraploid hybrids obtained by colchicine treatment of the completely sterile F1 diploid hybrids revealed very low and erratic fertility. A great variation in the fertility between seedlings was the rule.There is no apparent relation between chromosome pairing at MI and fertility of the allotetraploid vines. Average bivalent formation in the allotetraploids varied between 25.0 and 31.1 per cell compared to the expected 39 if complete pairing occurred.In all of the allotetraploid seedlings dominance of V. rotundifolia morphological characters was evident, although several exceptions were noted.Autotetraploid clones of the two species could be hybridized only by using V. vinifera as a female and V. rotundifolia as a male parent.Crossing behaviour of the allotetraploid F1 hybrids is identical to diploid VR hybrids. Hybrids are crossable among themselves; they can be crossed successfully only as female parents to V. rotundifolia and as female or male parent to V. vinifera.A chromosomal ratio hypothesis is proposed to explain the unilateral crossability pattern between the two species and their hybrid derivaties. The alternative breeding procedures are given for testing this hypothesis

Induction of sex conversion in male Vitis

Shoot girdling, widely different levels of nitrogen and photoperiod and a number of chemical agents were ineffective in promoting sex conversion in a male V. vinifera (sylvestris) clone 030-44.The cytokinins SD 8339, zeatin, benzyladenine and kinetin converted sex from male to hermaphrodite in the clone 030-44. The first two cytokinins were more effective than the others. A concentration of 1000 ppm of SD 8339 was the most effective, followed in decreasing order by 500 and 100 ppm. Treatment was most effective at the time of megaspore mother cell formation.SD 8339 also induced sex conversion in other male clones and seedling vines of V. vinifera L. (sylvestris) and in male clones of other Vitis species, and a species hybrid 'Ganzin 1'.In male clones and seedling vines of V. vinifera L. (sylvestris), there was no correlation in frequency of natural sex conversion and that induced by SD 8339, but such a correlation was found in male clones. of other Vitis species and a species hybrid.The cytokinins did not affect pollen viability and the seeds obtained germinated normally.Association of natural sex conversion with endogenous cytokinins in male vines of Vitis is discussed.Two possible practical applications of this method of sex conversion by cytokinins are also mentioned

Studies on sex conversion in male Vitis vinifera L. (sylvestris)

The appearance of functionally hermaphroditic flowers and mature seeded berries on otherwise male vines was defined as a natural sex conversion from functionally male to functionally hermaphroditic flowers. Sex conversion was investigated in vegetatively propagated vines of the wild male V. vinifera clone 030-44 derived from a seed sample collected in Iran. Frequency of sex conversion varied markedly among inflorescences on the same vine, among vines side by side, and from season to season, which implicated the effect of environment, both local and seasonal.Studies on vegetative selection for high fruitfulness revealed that sex conversion was not due to somatic mutation or any vegetative syndrome within the vine

Conversion and determination of sex in Vitis vinifera L. (sylvestris)

Sex conversion in the male V. vinifera (sylvestris) clone 030-44 could not be attributed to germinal mutation of the major gene for sex. The differences in sex expression among male seedling vines can best be explained on the basis of an undetermined number of minor modifying genes able to shift a very sensitive threshold. The frequency of sex conversion within a given seedling vine was greatly influenced by environmental, both local and seasonal, conditions. The following facts were established in Vitis vinifera L. (sylvestris): (1) the male sex is heterogametic and is inherited as a simple Mendelian factor, maleness being completely dominant;(2) homozygous males are as viable as heterozygous males, they are phenotypically alike and can only be identified by breeding tests;(3) pure and hermaphroditic males are genetically alike as far as the major gene for sex is concerned;(4) sex chromosomes are not differentiated, either morphologically or physiologically.A pair of alleles, SuF and Sum, were used to explain the results obtained on selfing the hermaphroditic male clone 030-44. The gene SuF determines maleness and its allele Sum in homozygous condition determines femaleness. The gene SuF is completely dominant over its allele Sum. The genotypes of the homozygous and heterozygous males are SuF SuF and SuF Sum respectively, and that of the female is Sum Sum. The evolution of cultivated V. vinifera hermaphrodites in the light of present results is discussed

The Vitis vinifera x V. rotundifolia hybrids as phylloxera resistant rootstocks

In greenhouse and field tests of rooted vines and seedlings, a considerable number of vinifera X rotundifolia F1 hybrid clones exhibit high tolerance or immunity to the root form of phylloxera, as judged by the formatirm of lesions or the insects found lodged on the roots.The formation of root lesions is related to the anatomical structure, the more closely it resembles the rotundifolia, the fewer and smaller the lesions.Phylloxera samples from five different areas in California have not been found to differ in gross morphology or in their reaction to the VR hybrids.The species rotundifolia contributes genes exhibiting considerable dominance for resistance in the F1 generation.Unlike the rotundifolia parent, the VR hybrids can be successfully used as rootstocks for vinifera grapes, although observations are only for eight years and hence preliminary.Although the VR hybrids are less easy to propagate than many common rootstocks, the variation is great enough between clones to permit selection