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1.
Summary High ergot (Claviceps fusiformis Loveless) susceptibility of pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids has often been associated with the A1 cytoplasm of male-sterile lines (A-lines). To understand the underlying basis of this association and to examine the prospects of breeding ergot-resistant hybrids, we evaluated 56 hybrids and their 15 parental lines for ergot reaction and selfed seedset for 2 years in disease nurseries at ICRISAT Asia Center. Hybrids were made by crossing seven pollen parents (2 susceptible and 5 resistant) onto two resistant and two susceptible A-lines, and their four corresponding maintainer lines (B-lines). A-lines had no selfed seedset while B-lines had 32–75% selfed seedset. Hybrids of A-lines had significantly less selfed seedset than the hybrids of the corresponding B-lines. The reduced seedset of A-lines and their hybrids, however, was not always accompanied by significantly higher ergot susceptibility. Highly resistant hybrids were obtained where both A-lines and pollen parents were highly resistant, regardless of male fertility levels of the hybrids. Thus, although the A1 cytoplasm, by its reduction of male fertility, had a large and significant effect in increasing ergot severity of hybrids, the contribution of nuclear genetic factors of female parents was about 1.8 times larger than that of the cytoplasm.Submitted as JA No. 1776 by the International Crops Research Institute for the Semi Arid Tropies. 相似文献
2.
Commercial viability of three cytoplasmic-nuclear male sterility (CMS) systems (A4, A5 and Av) as potential alternatives to the most widely used A1 system in pearl millet (Pennisetum glaucum (L.) R.Br.) was evaluated in terms of stability of complete male sterility of four isonuclear A-lines (81A1, 81A4, 81A5 and 81Av) and the level and stability of male fertility restoration of their 44 single-cross hybrids. Lines 81A4 and 81A5 had no pollen shedders (PS), and there were very low frequency of non-PS plants of these A-lines that had a maximum of 1–5%
selfed seedset (SSS). In 81A1 and 81Av,there were, albeit low frequency (<1%) of PS plants, and relatively higher frequency of the non-PS plants in these two lines,
the more so in 81Av,had 1–5% and even greater SSS. Some hybrids made on each of the three A-lines (81A1, 81A4 and 81Av) had high and stable male fertility, while others made on the same three A-lines displayed large variation in SSS across
the environments, the more so in case of hybrids made on 81Av. These results indicate that the A4 CMS system provides a better alternative to the A1 CMS system, while the Av system does not. On the basis of highly stable male sterility and the highest frequency of pollinators behaving as maintainers,
the A5 CMS system appeared to be the best for A-line breeding. The commercial viability of this CMS system in breeding R-lines of
grain hybrids, however, still remains to be ascertained as no hybrid on it was fully male fertile in any environment.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Summary Effect of A1 male sterile cytoplasm on smut severity in pearl millet (Pennisetum glaucum (L.) R.Br.) was studied by comparing 35 pairs of F1 hybrids, each pair carrying male sterile and normal cytoplasm. Mean smut severity was not significantly different in the hybrids carrying male sterile or normal cytoplasm. This suggests that in pearl millet male sterile cytoplasm is not associated with higher smut susceptibility. Partitioning of variance into different components showed that pollinators, A/B line pairs and their interaction primarily influenced smut severity of hybrids. Smut susceptibility might be attributed to effects of cytoplasm × nuclear interactions. 相似文献
4.
Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids, grown widely in India and to some extent in the US, are all based on an A1 CMS source, leaving the pearl millet hybrids vulnerable to potential disease or insect pest epidemics. A comparison of this
CMS system with two additional CMS systems (A4 and A5) in the present study based on isonuclear A-lines (seed parents) and their isonuclear hybrids showed that A-lines with the
A4 cytoplasm had much fewer pollen shedders and much reduced selfed seed set in visually assessed non-shedding plants as compared
to those with the A1 cytoplasm. A-lines with the A5 cytoplasm had neither any pollen shedders nor did they set any seed when selfed. This showed that the A5 CMS system imparts complete and most stable male sterility, followed by the A4 and A1 CMS systems. The frequency of maintainers, averaged across a diverse range of 26 populations, was highest for the A5 CMS system (98%), followed by the A4 (59%) and the A1 (34%) system indicating the greatest prospects for genetic diversification of A-lines lies with the A5 cytoplasm, and the least with the A1 cytoplasm. Mean grain yield of hybrids with the A1 cytoplasm was 5% more than the A4-system hybrids, while there was no difference between the mean grain yield of hybrids based on A1 and A5 CMS systems. Based on these results, it is suggested that seed parents breeding efficiency will be the greatest with the
A5 CMS system, followed by the A4 CMS system, and least with the currently commercial A1 CMS system. 相似文献
5.
Summary Sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is one of the most important pests of grain sorghum worldwide. We studied the reaction of midge-resistant and midge-susceptible genic-cytoplasmic male-sterile (A-lines) and their maintainers (B-lines), and the effect of resistant and susceptible restorers on sorghum midge. Midge damage and adult emergence were significantly lower on the B-lines of midge-resistant genotypes (PM 7061 and PM 7068) than their corresponding A-lines, while the reverse was true for the midge-susceptible genotypes (296A and ICSA 42). Differences in midge damage and the number of midges emerged were not significant between the midge-resistant and midge-susceptible A-lines when infested without pollination (except midge emergence on PM 7061A). Pollination with a midge-resistant restorer (DJ6541) reduced midge emergence significantly in one of two seasons. Source of pollen did not influence midge emergence on the highly-resistant A-line, PM 7061A. The implications of these observations in the development of midge-resistant hybrids were discussed. 相似文献
6.
Summary The shoot fly, Atherigona soccata is an important pest of sorghum, and host plant resistance is one of the most effective components for managing this pest.
Most of the hybrids grown in India based on milo cytoplasm (A1 cytoplasm) are highly susceptible to shoot fly. Therefore, the present studies were undertaken to evaluate different male-sterile
cytoplasms (CMS) for their relative susceptibility to sorghum shoot fly. Oviposition and deadheart formation were significantly
lower on the maintainer lines as compared to the corresponding male-sterile lines. Among the cytoplasms tested, A4M cytoplasm showed antixenosis for oviposition and suffered lower deadheart formation than the other cytoplasms tested. The
A4G1 and A4M cytoplasms suffered lower deadhearts in tillers than the other cytoplasms. Recovery following shoot fly damage in A4M, A3, and A2 cytoplasms was better than in the other cytoplasms tested. The larval and pupal periods were longer and male and female pupal
weights lower in A4M and A4VzM CMS backgrounds compared to the other CMS systems. Fecundity and antibiosis indices on CMS lines were lower than on the
B-lines. The A4M cytoplasm was found to be relatively resistant to sorghum shoot fly, and can be exploited for developing shoot fly-resistant
hybrids for sustainable crop production in future. 相似文献
7.
Summary Several hybrids between Oryza sativa and O. glaberrima and their backcrosses with O. sativa were studied. Their seed sterility was very different; large differences were also observed in the level of pollen sterility and in the earliness of microspore failure. The proportion of aborted embryo sacs was much lower than the rate of sterile male gametophytes. The backcross populations were much more sterile than the corresponding F1 hybrids. On the base of our observations and according to the literature, we may conclude that genic unbalance is the main cause of sterility of these hybrids, but that physiological factors may also be involved. Thus a restoration of fertility is generally possible by selection. On the other hand, male-sterile lines could be bred from some of these hybrids. 相似文献
8.
Summary Cabbage hybrid seeds are commercially produced by means of self-incompatibility. This system may show some instability mainly under tropical conditions, where cytoplasmic male sterility can be an alternative approach for hybrid seeds production. However, cabbage hybrids holding Ogura male-sterile cytoplasm show some irregularities during development. By assessing some characteristics during the growing cycle of male-sterile cabbage hybrids and comparing them to genomic similar male-fertile ones and to the most common cabbage hybrid cultivated in Brazil, it was observed that the male-sterile hybrids had the same vigour, uniformity, number of leaves, resistance to Xanthomonas campestris pv. campestris, and earliness as their male-fertile counterparts and performed better than the commercial check hybrid for some of these characteristics. Although male-sterile hybrids showed yellowing of leaves, some parental combinations succeeded in overcoming or strongly reducing this cytoplasmic effect.Abbreviations dat
days after transplanting
- CMS
Cytoplasmic Male Sterility
- CNPH
National Centre for Vegetable Crops Research 相似文献
9.
An investigation was carried out to assess the efficiency of A2 cytoplasmic-nuclear male-sterility (CMS) system in comparison to the widely used A1 cytoplasm in terms of general combining ability (gca) effects of male-sterile (A-) lines and mean performance, specific combining ability (sca) effects and mid-parent heterosis of hybrids for days to 50% flowering, plant height and grain yield at International Crops
Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India in 2001 and 2002 rainy seasons. The material
for the study consisted of six pairs of iso-nuclear, allo-plasmic (A1 and A2) A-lines and 36 iso-nuclear hybrids produced by crossing these A-lines with three dual restorer (R-) lines. The results revealed
that cytoplasm and its first-order interaction with year, R- and A-lines did not appear to contribute to variation in iso-nuclear
hybrids for plant height and grain yield. Cytoplasm had limited effect on gca effects of A-lines and on sca effects and mid-parent heterosis of iso-nuclear hybrids for days to 50% flowering, plant height and grain yield. The mean
days to 50% flowering, plant height and grain yield of A2 cytoplasm-based hybrids were comparable with those of widely used A1 cytoplasm-based hybrids. The relative frequency of the occurrence of the A1- and A2-based hybrids with significant sca effects and mid-parent heterosis indicated that A2 CMS system is as efficient as A1 with a slight edge over A1 for commercial exploitation. The implications of these results are discussed in relation to opportunities for broadening
not only cytoplasm base but also nuclear genetic base of both the hybrid parents. 相似文献
10.
Stability of male-sterile sources and fertility restoration of their hybrids in pearl millet 总被引：1，自引：0，他引：1
Genetic background has a significant effect on the expression of cytoplasmic-nuclear male sterility (CMS) in pearl millet (Pennisetum glaucum (L.) R. Br.). Therefore, a reliable characterization of CMS sources requires the use of near-isonuclear lines and their hybrids. We used this approach to characterize five CMS sources (A1, A2, A3, Av, and A4). Male sterility of 81A4 was the most stable, followed by 81A1 and 81Av, indicating the relative merits of these CMS sources in breeding stable male-sterile lines. Male-sterile lines 81A2 and 81A3 were highly unstable, indicating their minimal value. Differential male fertility restoration patterns of hybrids made on 81AV and 81A4 suggest that the Av and A4 cytoplasms represent CMS systems that are different from each other and from A1, A2 and A3. An evaluation of topcross hybrids of 15 diverse populations made on 81A1 and 81A4 showed that each population had restorers and maintainers of both cytoplasms and that the frequency of maintainers of A4 was as high as, or higher than, that of the A1 cytoplasm. Thus, use of the A4 cytoplasm can substantially increase the probability of breeding stable male-sterile lines based on inbreds developed from diverse genetic backgrounds, and also provide the opportunity for breeding restorers from each of these diverse genetic sources. 相似文献
11.
Summary To determine the distribution and geographic specificity of sterility maintainers in pearl millet, Pennisetum americanum (L.) Leeke, 428 diverse pearl millet germplasm accessions representing variation from 12 countries were crossed with a male-sterile line 5141A. The F1 hybrids were classified as male-fertile or male-sterile based on the seed set on bagged ear heads and an other morphology. Among these, 87 (20.3%) were classified as male-fertile, 32 (7.5%) as male-sterile, 282 (65.9%) as segregating for male-fertile/male-sterile and 27 (6.3%) behaved as male-fertile in the rainy and male-sterile in the postrainy season. Restorer lines were distributed in all the countries studied except Cameroon and USSR. Maintainer lines were observed from six countries but were concentrated in India. These maintainer lines differ from one another in several morphological and agronomic characters such as flowering, plant height, spike length and grain size. They may prove to be useful sources of material for generating new male-sterile lines. The restorers can be used to produce commercial hybrids.Submitted as J.A. No. 719 by the International Crops Research Institute for the Semi-Arid Topics (ICRISAT). 相似文献
12.
Pearl millet (Pennisetum glaucum (L.) R. Br.) cultivars for marginal, arid environments need to combine the adaptation to stress conditions of indigenous landraces with an improved yield potential and disease resistance, to allow them to both perform well in farmers fields and to meet the requirements for cultivar release. This paper evaluates landrace-based topcross hybrids (adapted landraces crossed on high-yielding male-sterile lines), as a quick and efficient way of achieving this objective. Topcross hybrids showed a consistent increase in biomass production across all test environments, including the harsh arid zone environments. Depending upon the plant type of the male-sterile used to make the hybrid, this was expressed as increased grain yield only, or increased grain and fodder yields. The downy mildew (Sclerospora graminicola) reaction of the topcross hybrids was determined by the reaction of the male-sterile line used, with the resistant male-sterile producing resistant topcross hybrids and vice-versa. Topcrossing adapted landraces on high-yielding male-sterile lines thus provides an opportunity to improve disease resistance and grain and/or fodder yields, with no apparent loss of adaptation to the marginal environments in which the landraces have evolved.ICRISAT Journal Article no. 1575 相似文献
13.
Cytoplasmic male sterility (CMS) is considered an efficient genetic tool in pearl millet hybrid breeding. Of the several CMS
sources available in pearl millet, A1 is the only CMS widely exploited to produce commercial hybrids in India. To explore the possibility of using alternate CMS
sources, we studied the cytoplasmic effects of different CMS sources on agronomic characters in pearl millet. Five CMS (A)
lines representing A1, A2, A3, A4 and A5 cytoplasms, their respective maintainer (B) lines and eight restorer (R) lines were used to generate 40 A × R and B × R experimental
crosses. The experimental material was evaluated at two different locations in India. Analysis of combining ability and heterosis
revealed that A4 and A5 cytoplasms had desirable effects for earliness. The A5 CMS was found to be particularly promising, as compared to other CMS sources for improving grain yield. The study also indicated
that the cytoplasmic effects on general combining ability (GCA) for various agronomic characters were largely non-significant.
However, cytoplasmic effects on specific combining ability and heterosis were found to be modulated by cytoplasmic-nuclear
interactions and influenced by the environmental conditions. The study also demonstrated the advantage of utilizing diverse
male-sterile and restorer combinations in maximizing the productivity as well as for genetic and cytoplasmic diversification
of hybrids in pearl millet. 相似文献
14.
Summary Intergeneric hybrids (F1) Diplotaxis erucoides (DeDe) x Brassica napus (AACC) and the first backcross to B. napus (BC1) have been obtained through in vitro culture of excised ovaries. The chromosome numbers of F1 and BC1 plants proved the occurrence of unreduced gametes. The study of metaphase I chromosome pairing showed that autosyndesis in De genome and allosyndesis between De and A/C genomes might exist. The male fertility of the F1 plants was low. Some male-sterile plants were found in F1 and BC1 progeny. The possibilities of creating addition lines B. napus-D. erucoides and of obtaining a new cytoplasmic male sterility in B. napus are discussed. 相似文献
15.
Sorghum midge, Stenodiplosis sorghicola (Coquillett) is one of the most important pests of grain sorghum worldwide. We studied the inheritance of resistance to sorghum
midge and compensation in grain weight and volume in panicles of sorghum hybrids and their parents under uniform infestation
(40 midges per panicle for two consecutive days). Sorghum midge damage ranged from 8.2 to 82.4% in the maintainer lines (B-lines)
of the females parents (A-lines), and 9.0 to 67% in the male parents (restorer lines). Hybrids involving resistant × resistant
parents were highly resistant, while those involving resistant ×susceptible and susceptible × resistant parents showed moderate
susceptibility. Susceptible × susceptible hybrids were susceptible. Compensation in (percentage increase) grain weight and
volume in midge-infested panicles of midge-resistant parents and their F1 hybrids was greater than in midge-susceptible parents and hybrids. General combining ability effects for midge damage, and
grain weight and volume were significant and negative for the midge-resistant females (ICSA 88019 and ICSA 88020), whereas
those for the midge-susceptible females (ICSA 42 and 296A) were significant and positive. However, the reverse was true in
case of compensation in grain weight and volume. Inheritance of compensation in grain weight and volume and resistance to
sorghum midge is controlled by quantitative gene action with some cytoplasmic effects. Resistance is needed in both parents
to realize full potential of midge-resistant hybrids.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
A new cytoplasmic-nuclear male sterility system in pearl millet 总被引：1，自引：0，他引：1
K. N. Rai 《Plant Breeding》1995,114(5):445-447
Among the cytoplasmic-nuclear male sterility (CMS) systems reported in pearl millet, Pennisetum glaucum (L.) R. Br., the Am= A4 system produces the highest frequency of male-sterile hybrids. A CMS source identified in a large-seeded gene pool (LSGP) was compared with the A4 system. Seven diverse restorer lines of the A4 system produced hybrids with 81A4 that were all fertile (pollen-shedding score 4 and 68–89% selfed seedset). In contrast, all the hybrids of these inbreds made with the isonuclear line with the LSGP cytoplasm were sterile (pollen-shedding score 1 and 0–3% selfed seedset). Topcross hybrids of four diverse composites made with 81A4 had 10–35% plants that had good fertility (> 50% selfed seedset). In comparison, no plant of any topcross hybrid with the isonuclear line having LSGP cytoplasm exceeded 20% selfed seedset, and it was rare for a plant to exceed even 10% selfed seedset. These differential fertility restoration patterns of hybrids indicate that the LSGP cytoplasm represents a CMS system that is different from the A4 and, by implication, from all those reported to date. This new CMS system is designated A5. 相似文献
17.
Summary Barriers to interspecific hybridization in Trifolium were investigated by manipulation of mentor pollen treatments, ploidy levels, and compatibility and male sterility systems. Crosses involving the addition of mentor pollen produced fewer seeds and hybrids than crosses involving normal pollination. Lower seed set with mentor pollen was deduced to result from the use of less viable pollen, approximately half the pollen having been killed by alcohol. Pollinations at the diploid level resulted in more hybrids than at the tetraploid level, perhaps because genes for male sterility produced higher female sterility in the tetraploids. The self-compatible stock produced more seeds, mostly selfs, than the self-incompatible stock, but produced more hybrids only in one cross, T. pratense L. × T. diffusum
Ehrh. The use of male-sterile female parents reduced selfing but produced fewer hybrids than male-fertile female parents. Techniques of this study were designed to affect prefertilization barriers, but the lack of effect may indicate that postfertilization barriers in Trifolium are of greater importance.Journal Article No. 98-3-208 of Kentucky Agricultural Experiment Station. Published with approval of the Director. 相似文献
18.
Summary Apomixis has been reported in a few lines of sorghum, among them R473 which was originally reported to be an obligate apomict. Although this line has multiple embryo sacs, the frequency of apomictic seed formation has not been determined because a progeny test has not been possible. R473 does not cross as a female with other lines except when its own pollen is present. In the present study mutations were induced in R473 by hydrazine and irradiation. Crosses were made between male-sterile mutants as females and normal R473 as males. Plants of R473 produced F1 hybrids sexually, thus indicating that they were not obligate apomicts. These F1's also reproduced sexually, as indicated by segregation for male sterility and male fertility in F2 progenies. 相似文献
19.
Most of the cytoplasmic-nuclear male-sterile (CMS) lines of soybean were developed only from a limited cytoplasm sources and performed not as good as required in hybrid seed production, therefore, to explore new male-sterile cytoplasm sources should be one of the effective ways to improve the pollination and hybridization for a better pod-set in utilization of heterosis of soybeans. In the present study, total 80 crosses between 70 cultivated and annual wild soybean accessions and three maintainers (N2899, N21249, and N23998) of NJCMS1A were made for detecting potential new sources with male-sterile cytoplasm. The results showed that in addition to the crosses with N8855.1 (the cytoplasm donor parent of NJCMS1A) and its derived line NG99-893 as cytoplasm parent, there appeared three crosses, including N21566 × N21249 and N23168 × N21249, with male-sterile plants in their progenies. According to the male fertility performance of backcrosses and reciprocal crosses with the tester N21249, the landrace N21566 and annual wild soybean accession N23168 were further confirmed to have male-sterile cytoplasm. Accordingly, it was understood that the source with male-sterile cytoplasm in soybean gene pool might be not occasional. The results also showed that the genetic system of male sterility of the newly found cytoplasm source N21566 was different from the old cytoplasm source N8855.1, while N23168 was to be further studied. Based on the above results, the derived male-sterile plants from [(N21566 × N21249) F1 × N21249] BC1F1 were back-crossed with the recurrent parent N21249 for five successive times, and a new CMS line and its maintainer line, designated as NJCMS3A and NJCMS3B, respectively, were obtained. NJCMS3A had normal female fertility and stable male sterility. Its microspore abortion was mainly at middle uninucleate stage, earlier than that of NJCMS1A and NJCMS2A. The male fertility of F1s between NJCMS3A and 20 pollen parents showed that 7 accessions could restore its male fertility and other 13 could maintain its male sterility. The male sterility of NJCMS3A and its restoration were controlled by one pair of gametophyte male-sterile gene according to male fertility segregation of crosses between NJCMS3A and three restorers. The nuclear gene(s) of male sterility in NJCMS3A appeared different from the previously reported CMS lines, NJCMS1A and NJCMS2A. The development of NJCMS3A demonstrated the feasibility to discover new CMS system through choosing maintainers with suitable nuclear background. 相似文献
20.
Summary F1 hybrids of triazine resistant Brassica napus and triazine susceptible B. oleracea were morphologically intermediate to the parent species. Of 49 hybrids examined, 44 had 28 chromosomes, two had 37, one had 38 and two had 56. The 38-chromosome plant was thought to be a matromorph, the others, A1C1C (28), A1C1CC (37) or A1A1C1C1CC (56) type hybrids. Pollen stainability averaged 9.0% in the sesquidiploid, 32.0% in the tetraploids and 89.5% in the hexaploids. All the interspecific hybrids were resistant to 1.0×10-4 mol L-1 atrazine. The sesquidiploid hybrids produced gametes with chromosome numbers ranging from 9 to 17 and the tetraploid hybrid gametes had chromosome numbers from 15 to 22. Most hybrids produced self-seed. The partial fertility of these hybrids may permit their backcrossing to one or both parents. 相似文献