摘要:

AbstractA description is given of the major modification induced in the pattern of photosynthates accumulation by the delayed senescence behaviour of the maize inbred line Lo87602. The major effects noted are: (1) high water and chlorophyll contents in leaves at physiological maturity, (2) high sucrose content in the stalk during grain filling, (3) busks and cobs with more water, sucrose and proteins, (4) high protein content in the grain. The high level of sucrose in the stalk at physiological maturity protects the plant from stalk rotting organisms.The delayed senescence phenotype depends on a major dominant gene, the same genetic factor which favours the accumulation of a high level of sucrose in the stalk.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01053.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA dominant gene inducing male sterility in wheat is described. It is located on the short arm of chromosme 4D with a recombination percentage of 31.16 with the centromere. The potential use of this allele in breeding and cytogenetic studies in both tetraploid and hexaploid with is discussed.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01054.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractWhen the flowers are not disturbed, the yield of F1hybrids of faba beans normally exceeds that in their inbred parents. The basis of this “heterotic autofertility” was investigated by examining flowers for pollination and fertilization throughout the flowering season and assessing the distribution of seeds and pods on mature plants. Six inbred lines and seven of their F1hybrids were grown without protection from bee visitation, and their autofertility was estimated’ by comparing their fertilization with that of cytoplasmic male‐sterile line. The first direct evidence was obtained that heterotic autofertility acts by increasing; the proportion of flowers which were pollinated and fertilized. The autofertility was not perfect, especially in a closed‐flower hybrid, as many ovules remained unfertilized. Several factors contributed to the number of seeds per pod in F1hybrids, being superior to parental means: (1) more ovules per flower, (2) greater fertilization of the basal ovules, (3) reduced abortion of the apical ovules and (4) greater overall maturati

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01055.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractGrowth rate and harvest index are the primary components that cause variation in gram yield or oats it growth duration of the crop is fixed as it is in mid western USA. Because harvest index for oats in that region has been optimized 45 %, growth rate is the only remaining trait for improving grain yield.F2derived oat lines from inter‐ (Avena sativaL. ×A. SterilisL.) and intraspecific mating (amongA. sativacultivars) in F3were selected for vegetative growth rate at maturity (GRM) with an intensity of 8.3%. Predicted genetic gain was 21.5% for GRM, and actual gain was 7%. Changes in grain, biological, and straw yields were higher than gains in GRM when expressed as percentages of the oat population means. Predicted genetic gains were very low for traits unrelated or negatively associated with GRM such as heading data and harvest index. This study suggests that indirect improvement can be made for gain, biological, and straw yields by selecting for G

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01056.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPrecocious centromere division at metaphase I leading to diploid gamete formation has been observed in three cultivars. Some of the PMC's are characterized only by rod bivalents whose centromeres split at metaphase I. After passing to respective poles, the already divided centromeres fall apart at telophase I, with the result that each pole has unreduced number of 34 chromosomes. There is no second division and such cells form dyads which give rise to diploid pollen grains. Such unreduced pollen are 100 per cent fertile because of reduced (or no) recombination between hamoeolugous genomes and the presence of two sets of chromosomes. Thus, triploids or even tetraploids can arise when such pollen grains are involved in tertilization with reduced or unreduced egg of other cultivars.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01057.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractHeritability estimates for soluble solids, bulb firmness and bulb weight were carried out in two ways, namely, parent‐offspring regression and half‐sib family intra‐class correlation. Leaf characters were estimated only by half‐sib intra‐class correlations. For soluble solids the values were high (72% and 58% respectively), while the values for bulb weight And bulb firmness were low (20% and 39%, and 32%, and 33% respectively) using the two methods. Some high additive genetic correlations were observed between bulb firmness and length of longest leaf (rA= 0.830), bulb weight and leaf area of longest leaf (r

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01058.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractSeedlings from 27 open pollinated cas‐hew genotypes in two environments with five replications in each location were used to investigate the genetic, the environmental, and the nut size effects on cashew seedling vigour during the 12‐week pretransplantation period.Enviromental variances, genotype × environment interactions, and broadsense heritability values for the eight studied traits indicated that emergence percentage (L %) and seedling height (SH) were more reliable indices for seedling vigour, since they were more heritable and less influenced by the environment. Seedlings from large cashew nuts were consistently more vigorous than those from small nuts, probably because of the larger food reserve in the two cotyle

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01059.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPlant regeneration from callus cultures may provide a source ot somaclonal variation for the improvement ot the apomictic grassPoa pratensisL. It is first necessary to be able to induce callus and regenerate plants in this species at a high frequency. Variation was observed between 50 cutivars ofPoa pratensisfor callus induction and plant regeneration. Using the cultivars ‘Merion’ and ‘Victa’, three basal media were tested along with various media additives. Murashige and Skoog's basal medium with 0.2 mg 1−12,4‐dichlorophenoxyacetic acid, 0.1 mg 1−16‐benzylamanopurine, 100 mg 1−1casein hydrolysate and 25 g 1−1sucrose is considered to be a good medium for callus growth and plant regeneration. Embryo‐like structures were observed in the callus of some cultivars but plant regeneration appeared to be predominantly from shoot meristems on the callus surface. The majority of regenerated shoots were green, but chlorophyll deficient shoots were obtained from media containing coconut milk. Green plantlets could be transferred to so

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01060.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractFused protoplasts between different dihaploid genotype of potato were cultivated in small droplets of liquid medium. It was observed that divisions and sustained development of these protoplasts could only be achieved it they had contact via gas phase to other living cells. The factor being responsible for this effect could not be identified. Nevertheless it was possible under such a culture condition to regenerate somatic hybrid calli from heterokaryons of various fusion combinations of potato.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01061.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe genetic determination of the plant regeneration ability of tissue cultures arising from immature embryos was studied using a ‘Chinese Spring’/‘Cheyenne’ substitution series. Plant regeneration proved to be polygenically determined. In tile current experiment the chromosomes 7B, 7D and ID were found to be effective, although the possibility of other chromosome effects cannot be e

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1986.tb01062.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY