摘要:

AbstractIn order to study the effects of competition on the genotypic composition of chance‐hybrids inLoliuni multiflorum, eight chance‐hybrids were produced according to Burton (1948). Inbred lines and cultivars were used as parents. The proportions of parental and hybrid components in the seeds and growing‐field stands of the chance‐hybrids were determined over three cuts using gel electrophoresis. The realized hybrid proportions in the seeds, at a maximum of 38.3%, were considerably lower than the theoretically expected 50%. In the field stands, the hybrid proportions of the chance‐hybrids derived from inbred lines increased considerably and continously over cuts, whereas those of the chance‐hybrids produced from cultivars increased only slightly. A maximum hybrid tiller proportion of 76.8% was found at the third cut. Correspondingly, the total yield of the chance‐hybrids produced from cultivars was only slightly higher than that of the parents. The production of chance‐hybrids, therefore, proved to be sensible only if inbred lines had been

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00760.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe influence of different tuber compounds on susceptibility to wire‐worms (Agriotes obscurus) was studied in experiments with 10–13 potato genotypes. Both greenhouse and field experiments showed that the susceptibility to wireworm attack was negatively correlated with the concentration of glycoalkaloids and positively correlated with the concentration of reducing sugars in the outer 2 mm of the tubers. Varietal differences in chlorogenic acid had no effect on susceptibility. Breeding for high levels of glycoalkaloids in the extreme periphery, but very low levels in the rest of the tuber, will protect the tubers from wireworms and yet result in acceptable glycoalkaloid levels for food saf

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00761.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractEight non‐allelic male‐sterile mutants controlled by a single recessive gene were induced in garden pea (Pisum sativum) after EMS, DES and gamma‐ray‐mutagen treatments singly and in combination. These mutants differ in the time and type of tapetal development due to differential action of male‐sterile (ms) genes over the sporogenous and non‐sporogenous anther tissue. In themsg1mutant, the sporogenous tissue breaks down during premeiosis, followed by tapetal degeneration. Inmsg2, sporogenous tissue and tapetal tissue exhibit anomalies at early and late prophase 1, respectively. Although inmsg3andmsg5the ms gene action over sporogenous tissue initiates during early and late prophase, respectively, the tapetal tissue breaks down during post‐meiosis. Inmsg6, anomalies in the sporogenous tissue appear during prophase II, but the tapetum degenerates during the mononucleate stage. Although both the tapetal and sporogenous tissue anomalies appear simultaneously at pachytene inmsg4, the tapetal breakdown is delayed until the microspore stage. Inmsg7andmsg8, anomalies in both these tissues occur simultaneously during the tetrad and post‐meiotic stages, respectively. Despite differences in the timing of tapetal and sporogenous tissue breakdown, tapetal development is normal inmsg1, msg5, msg6, msg7 and nisg8but abnormal inmsg2, msg3 and msg4.Themsgene action is dual inmsg2, msg3 and msg4but single inmsg1, msg5, msg6, msg7andmsg8.In all these mutants, the time of tapetal anomaly exhibits no correlation with the time ofmsgene action. The gene for open flower found in one male‐sterile mutant needs to be introduced into fertile peas for commercial hy

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00762.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTo analyse interactions in thePhytophthora capsici‐pepper (Capsicum annuumL.) system, three pepper lines (‘Morrón IN1A 224’, ‘PI201232’ and ‘SCM 334’) with various degrees of resistance toP. capsiciand threeP. capsiciisolates with increasing aggressiveness were used. Inoculations were made when plants had 4–6 leaves, either by irrigating the culture substrate withP. capsicizoospore suspensions at increasing concentrations of up to 3 × 105/ml, or by adding mycelial suspension.P. capsiciisolate ‘Ca’ was the least aggressive, followd by ‘8303’ and ‘Bl’. The logistic function was appropriate to describing cumulative mortalities of pepper seedlings inoculated with differentP. capsicizoo‐spore concentrations. The inoculum concentration required for 50% mortality classified pepper lines as susceptible (‘Morrón INIA224’) and resistant (‘PI201232’ and ‘SCM334’), the former being less resistant than the latter. Isolates ‘Ca’ and ‘8303’ caused very different mortalities both with zoospore and mycelial inoculations, which allowed them to be classified as belonging to two different vertical pathotypes (PO and PI). Isolate ‘Bl’ acted similarly to isolate ‘8303’ when inoculated on ‘Morrón’ and ‘SCM334’, but its behaviour was dependent on zoospore concentration when inoculated on ‘PI201232’. It also proved to be similar to ‘Ca’ using mycelial inoculation. As the case of ‘Bl’ would not be an exception amongP. capsiciisolates, the two vertical pathotypes PI and PO would be the higher (isolate ‘8303’) and lower (isolate ‘Ca’) limits of a range of aggressiveness. Although

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00763.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAnin vitroanther‐culture method has been improved by using young mother plants and by using frequent subcultures, thus increasing the androgenic yield in differentCapsicum annuumL. genotypes. An assortment of peppers was used, composed of 15 genotypes (four breeding lines, seven cultivars and four F1hybrids). A new system for qualifying the androgenic response was established. For use in practical breeding, a minimum of 5 % of plant regeneration was proposed as the criterion for a fair response. Accordingly, one excellent, one good and eight fair responses were identified among the genotypes investigated. As compared to the standard cultivar. 2 genotypes gave a significantly better response, i.e. ‘Fehérözön’ (75.8%) and ‘Szechuan 90716’ (21.0%). Incomparative investigations, F1hybrids, produced from crosses between poor/non‐responsive and responsive genotypes, showed a fair level of response, even the case of a poor response in donor parent. The ploidy level of the resulting plants was determined by flow‐cyt

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00764.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAnalyses of seeds from a wide range of pea lines have revealed extensive variation for all of the major fatty acids normally found in pisum. Unlike total lipid content, this variation was not affected by the presence of mutant alleles at the r and rb loci. To allow chemically analysed seed to be used in crosses, which is of particular importance for F2seed, a method has been developed by which individual seeds can be analysed non‐destructively. This system entails drilling a small hole in the seed, away from the embryonic axis. The small quantity of powder produced by this process can be used for the chemical analysis but does not prevent the seed from being grown to produce progeny. Reducing the sample size had no significant effect upon the compositional analysis of the fatty acid

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00765.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractSix ‘Chinese Spring/Triticum spelta’ substitution lines for chromosomes 1A, 1D (duplicates), 3D (duplicates), 6D, and one ‘Chinese Spring/ Marquis’ substitution line for chromosome 2B were studied for tissue‐culture response (TCR). The results reported here indicate that chromosomes 2B and 6D are critical for TCR, whereas chromosome ID affects callus weight only. Chromosomes 1A and 3D were not found to be critical, however, these chromosomes may carry genes with mino

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00766.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo meiotic mutants of L.tennis(2n = 2x = 12) producing unreduced pollen are described. When crossed to male sterileL. corniculatus(2n = 4x = 24) plants, all progeny plants were morphologically similar toL. corniculatus, had 2n = 24 chromosomes, and in the cross, were fully compatible withL. corniculatus, indicating that the male parent plants were 2n‐pollen producers. One of them also had ‘giant’ pollen grains. In metaphase II of both genotypes, there were parallel and tripolar spindles leading to dyad and triad formation, the latter being found most frequently. Since both the above‐mentioned mechanisms result in first‐division restitution‐type microspores, the genotypes examined could be useful in bre

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractFatty‐acid composition was studied in a half diallel in opium poppies using six parents, F1and F2. Poppy is an oleic‐linoleic‐acid type of crop with a low level of linolenic acid of up to 3% or only trace. Transgressive segregation was observed in F2having up to 81% linoleic acid making it suitable for development as a high‐linoleic‐acid crop. This is the first report of its kind in op

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Books reviewed in this article:Bradshaw, J. E. and G. R. Mackay (eds), Potato Genetics.Janick, J. and J. E. Simon (eds), New Crops.Damania, A. B.(ed.), Biodiversity and Wheat Improvement.Herrmann, B., and S. Hummel (eds), Ancient DNA. Recovery and Analysis of Genetic Material from Paleontological, Archaeological, Museum, Medical, and Forensic Specimens.Singh, K. B., and M. C. Saxena (eds), Breeding for Stress Tolerance in Cool‐season Food Legumes.Henry, R. J., and J. A. Ronalds (eds), Improvement of Cereal Quality by Genetic Engineering.Bowman, J. (ed.), Arabidopsis—an Atlas of Morphology and Development, 1st

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY