摘要:

AbstractGeneral (GVA) and specific (SVA) varietal ability quantify the value of genetic stocks as components for synthetic varieties. Additionally, these parameters can be used to predict the performance of the synthetics. The concept of varietal ability is known for completely allogamous crops. It has not yet been worked out for partial allogamy with a genotype‐dependent degree of cross‐fertilization. We have developed formulae to calculate GVA and SVA referring to generation Syn 1 in this general situation. The concept of varietal ability considers the influence of the components'per seperformance on the resulting synthetic variety. This influence increases with decreasing degree of cross‐fertilization. Thus, our formulae should be of special benefit to partially allogamous crops.The formulae are illustrated by a numerical example taken from our research onVicia fabaL. To estimate the relevant parameters forVicia fabeL., we propose to use two morphological markers (flowers and seed colour) simultane

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00561.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe rate of early embryo‐sac development was studied in seven faba bean (Vicia fabaL.) cultivars grown in a controlled environment. The embryo‐sac stage was determined from the number of endosperm nuclei per embryo‐sac and the number of embryo cells during the first 12 days after pollination. Differences in early embryo‐sac development were observed between the genotypes studied.In addition, five differentV. faba×V. narbonensiscrosses and reciprocals were made using genotypes with small differences in mean endosperm cell cycle time and genotypes with large differences. The percentage of success (pod set) inV. faba×V. narbonensiscrosses ranged between 9 % and 59 % while in the reciprocals it ranged from 12 % up to 30 %. However, cytological studies showed that the high percentage of success (pod set) observed in the cross A‐107 × A‐202 was not associated with a higher percentage of interspecific hybrid embryos.The results indicate that genotypes of the two species with smaller differences in mean endosperm cell cycle time result neither in a higher percentage pod set nor in bigger

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00562.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractPolymorphism and ontogeny of 11 chicory (Cichorium intybusL.) enzymatic systems have been analyzed by native polyacrylamide gel electrophoresis, namely: leucine aminopeptidase, phosphoglucomutase, shikimate dehydrogenase, glutamate oxaloacetate transaminase, superoxide dismutase, isocitrate dehydrogenase, esterase, phosphorylase, glucose‐6‐phosphate dehydrogenase, 6‐phos‐phogluconate dehydrogenase and glucose phosphate isomerase. The use of these systems as biochemical markers is di

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00563.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMicrosporogenesis of different, temperature‐ and tetracycline‐sensitive cms plants, and male fertile genotypes was investigated.The microsporogenesis of cms plants [(S)xx] and fertile plants [(N)xx or (S)X.]is similar up to the tetrade stage. During the tetrade stage, microspores of cms plants start to die off. The effect of the (S)‐cytoplasm on microsporogenesis is overcome by the restorer gene X, the temperature gene T and by tetracycline gene a. Whereas the X gene acts independently of environmental conditions, the gene T is expressed at constantly high temperature of 24 °C, and the tetracycline gene a acts after tetracycline treatment. After temperature‐ and tetracycline treatment, respectively, the sensitive genotypes need 10—14 days to change from male sterile into male fertile. This period seems to be most interesting to study the influence of the defined nuclear genes on mitochondrial transcription and t

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00564.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe objective of this study was to investigate the origin of chromosome segments of maize (Zea maysL.) inbred B86 from its parental inbreds B52 and Oh43 using RFLPS. B86 was selected to combine resistance to the first and second brood of the European corn borer with the favorable agronomic performance of Oh43. RFLP analyses of the three inbreds were performed with three restriction enzymes (EcoRI,EcoRV,HindIII) and 178 DNA probes covering all ten maize chromosomes. For two DNA probes in combination with one enzyme, B86 showed a new RFLP pattern not present in the two parents. Based on results from 119 polymorphic DNA probes, the proportion of the B86 genome contributed by B52 (51.3 %) and Oh43 (48.7 %) was almost equal.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00565.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe response of barley Composite Cross XLI to selection for resistance to leaf rust was evaluated. Representative samples from eight cycles of recurrent selection were inoculated with an isolate ofPuccinia bordeiOtth. in both the seedling and adult plant stage. Disease symptoms were evaluated 14 days after inoculation. The resistance in CC XLI increased with selection in the seedling stage from 15.1 to 20.5 %, and in the adult plant stage from 20.5 to 37.5 %, respectively. The largest gains in resistance were observed in the earlier cycles of recurrent selection. Significant fluctuations in percent resistant plants occurred between the years.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractHordeum bulbosumhas several desirable attributes, including disease resistance, which would be worthwhile transferring toH. vulgare.Despite homoeologous chromosome pairing in the interspecific hybrids, there have been few reports of successful gene introgression between the two species. A possible explanation for this is that recombinant male gametes are at a competitive disadvantage with normal balanced gametes during post‐pollination events. To circumvent this problem, the possibility of obtaining plants directly from immature pollen grains was investigated. Anthers from diploid, triploid and tetraploidH. vulgare × H. bulbosumhybrids were cultured on defined media. Only hybrids with dehiscent anthers in vivo responded in culture, and after transfer of calli and embryoids to regeneration medium, 36 albino and 12 green plants were obtained. Seven of the green regenerants survived, one of which contained 15 H. vulgare chromosomes (including one acrocentric chromosome) and oneH. bulbosumchromosome. Another regenerant (Ac166) resembled a diploidH. vulgare × H. bulbosumhybrid but had partial anther dehiscence and a slightly modified chromosome constitution. Mostly normal H. vulgare progeny were obtained from crosses betweenH. vulgarecv.‘Emir’ and Ac166, but three plants involved chromosome additions and substi

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAll wheat varieties (106) grown in the U.S. on more than 100,000 acres (38,610 ha) as of the latest (1984) crop variety survey were characterized by sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The high‐molecular‐weight glutenin subunit (HMW‐GS) band patterns for each variety were assigned the corresponding Payne numbers and theoretical quality scores based on those assignments. The subunit assignments were compared for the different wheat varieties and the five main wheat classes grown in the U.S. Hard red spring (HRS) and winter (HRW) wheats used mainly for breadmaking showed a remarkably high percentage of bands associated with good breadmaking quality. The allele 5+10, which has the strongest association with good quality, was present in 91 % of the hard red spring wheats and 62 % of the hard red winter wheats. Also, 91 % of all HRS and 53 % of HRW wheat varieties had quality scores of 9 or 10 (10 is the highest possible score). Evidently, by selecting for quality through close cooperation with quality testing laboratories, U.S. breeders have unknowingly selected for high quality glutenin subunits in their released varieties.HRS and HRW wheat varieties are normally grown in different environments in time and/or space, accounting to a large extent for differences in protein content (∼2 %) and other quality traits in the two crops. The uniformly high theoretical quality scores of the HRS wheats compared to more variable scores for HRW wheats may help to explain the popular perception that spring wheats have intrinsically higher quality than winter wheats. Admixing grain from variable (some poorer, most good) HRW wheat varieties (due to genetics or environment) has probably also led to the perception of overall lower quality for HRW than HRS wheats.In the soft red winter (SRW) and soft white (SW) wheat classes where the end‐use is typically cookies and cakes, 40 and 90 %, respectively, have the allele 2+12 that correlates with poor bread baking quality. The absence of alleles for good bread baking quality may be predictive of good quality for soft w

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractSix pearl millet (Pennisetum glaucum[L.] R. Br.) composites were subjected to three or more cycles of selection in multilocational yield trials and downy mildew disease nurseries in India. The base and selected populations were tested (a) over four years at three locations in India (11° to 29°N), (b) under terminal‐drought and optimal moisture conditions for two years, and (c) under induced downy mildew infections to determine the impacts of selection on grain yield, agronomic traits, and resistance to downy mildew (Sclerospora graminicolaSacc. Schroet.). Mean grain yield increases for four composites undergoing three to six cycles of selection ranged between 23 to 94 kg ha‐1cycle‐1(0.9 to 4.9 % cycle‐1) which, averaged over composites, amounted to 3.3 % cycle‐1. Yield gains were generally expressed at all test locations and under both terminal‐drought and optimal moisture environments. The gains in grain yield were associated with increases of both biomass and harvest index without extending the growth duration except in the earliest composite. Susceptibility to downy mildew remained below 10 % in all selected populations. Thus, the effectiveness of recurrent selection for increasing yield and yield stability of pearl millet is clearly

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractPurified cucurbitacin B and E act as feeding stimulants for the red pumpkin beetle, but on testing three pairs of isogenic bitter (Bi) and non‐bitter (bi) lines of cucumber, no relationship was found to exist between the bitter gene and the degree of damage caused by this beetle. In summer squash, both resistant and susceptible lines contain cucurbitacin at the susceptible plant growth stage (cotyledon) but there was no correlation between the quantity of total phenols, free amino acids or reducing sugars in this material and resistance. Bitter gourd, which has cucurbitacin in the cotyledons, was not preferred by the beetl

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1993.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY