Sclerotinia resistance in sunflower. II. Combining ability and midparent heterosis for reaction to ascospore infections at flowering

In Argentina, susceptibility of the sunflower crop to Sclerotinia sclerotiorum capitulum attacks can cause significant yield losses. We reported earlier two hybrids among a series obtained from crosses between inbred lines following a factorial mating design that had a sufficient level of resistance to be adapted to the main Argentina sunflower growing area. Results concerning the per se behavior of the parental lines involved in these crosses and the combining ability and heterosis effects of such parental genotypes are presented in this article. The lines showed different responses to white rot incidence and relative incubation period. There were significant effects for general and specific combining ability and also for midparent heterosis, for the two variables evaluated. Preponderance of additive gene effects on genetic control white rot resistance level was shown. The development of sunflower inbred lines to be used as parents in the production of hybrids for areas requiring moderately resistant hybrids is an important phase in breeding programs. To optimize the use of resources and time, our results suggest that testing general combining ability at early generations of selfing followed by testing of hybrids may be considered as an adequate strategy in breeding for white rot resistance.     

Resistance to Sclerotinia sclerotiorum of 'high oleic' sunflower inbred lines

Cultivation of sunflower (Helianthus annuus L.) is strongly affected by Sclerotinia sclerotiorum. To identify new sources of genetic diversity for sunflower breeding 25 sunflower inbred lines were analysed using eight Amplified Fragment Length Polymorphism (AFLP) primer combinations and their genetic similarities (GS) were estimated. Data were used to develop a Unweighted Pair Group Method using Arithmetic Averages (UPGMA) dendrogram. GS values of 0.58‐0.98 were observed but with no separate groupings dependant on oil quality. The inbred lines were screened for their reaction to inoculation with Sclerotinia sclerotiorum (Lib.) de Bary. Sunflower heads were artificially inoculated with S. sclerotiorum in three environments. Head infection was monitored after 1 week (lesion length) and 2 weeks (head rot). The F5 generation of a cross between a resistant (SWS‐B‐04) and a susceptible inbred line (SWS‐B‐01) was also tested for sclerotinia reaction across three environments. Significant differences in sclerotinia resistance, moderate heritabilities and a high correlation between the two assessments were observed. Inbred lines with a high level of resistance could be identified. These lines can be used for further breeding to improve sunflower sclerotinia resistance and to develop superior new hybrids.     

Interspecific hybrids of sunflower as a source of Sclerotinia resistance

Sclerotinia sclerotiorum is considered the most devastating pathogen of sunflower grown in humid environments. In this study, progenies of partial hybrids between Helianthus maximiliani, a wild species that has been shown to be resistant to S. sclerotiorum, and H. annuus were characterized by amplified fragment length polymorphism (AFLP) analysis to identify whether there are introgressions from H. maximiliani into the cultivated sunflower at the molecular level. Wild species‐specific fragments as well as fragments not found in either parent were detected. Progenies tended to cluster together according to the original partial hybrids in the dendrogram by the use of bootstrap procedures. The progenies were studied for their reaction to S. sclerotiorum using artificial inoculation of sunflower heads. Some of the progenies showed a higher level of resistance compared with resistant inbred lines. It was possible to identify two AFLP‐fragments which seem to be linked to Sclerotinia resistance.     

Effects of Early and Late Harvest on Agronomic Performance and Stability of Late Blight Resistant (R-gene Free) Potato Genotypes

Late blight is an important constraint to potato production and genotype resistance is an effective disease control mesure. Ten late blight resistant potato genotypes (R-gene free) were assessed for yield performance and stability at early (90 days) and late harvest (120 days) at two locations in Kenya during two years. Significant differences (P ≤ 0.05) in area under disease progress curves (AUDPC) were detected among potato genotypes. Resistant genotypes free of R-genes had significantly (P ≤ 0.05) higher yield at late than early harvest, perhaps due to increased tuber bulking period. The rank of genotypes for AUDPC, late blight resistance, and tuber yield varied across seasons and locations (environment). Additive main effects and multiplicative interaction (AMMI) analysis of tuber yield and late blight resistance resulted in significant (P ≤ 0.05) effects of genotypes (G) and environments (E). The proportion of genotypic variance was larger than the environmental variance and the G × E interactions. For tuber yield, the G, E, and G × E interactions accounted for 42.9, 39.6 and 17.5%; and 53.4, 29.7, and 16.9% at early and late harvests, respectively. For AUDPC, G, E, and G × E accounted for 80.2, 5.0, and 14.8%; as well as 82.3, 4.6, and 13% for early and late harvests, respectively. The resistance of potato genotypes without R-genes varied. Selective deployment of resistant genotypes can improve potato tuber yield.     

Molecular mapping of genomic regions harboring QTLs for stalk rot resistance in sorghum

Stalk rot, also called as charcoal rot in India, caused by Macrophomina phaseolina, is an economically important, soil borne disease in major sorghum growing areas across the world. A population of F₉ generation recombinant inbred lines (RILs), derived from IS22380 (susceptible) × E36-1 (resistant), along with parents were phenotyped in sick plots at two locations (Dharwad and Bijapur, Karnataka, India). A total of 85 polymorphic marker loci (62 nuclear and 4 genic SSRs, 19 RAPDs) was available for the construction of genetic map, spanning 650.3 cM in all the ten linkage groups. Analysis with QTL Cartographer (2.5b), adopting composite interval mapping method (LOD > 2.0) at both locations, revealed 5 QTLs at Dharwad and 4 QTLs at Bijapur locations for the component traits of charcoal rot disease resistance. QTLs for number of internodes crossed, length of infection and per cent lodging accounted for 31.83, 10.76 and 18.90 per cent at Dharwad location and 14.87, 10.47 and 26.44 per cent phenotypic variability at Bijapur location, respectively. The QTLs for number of internodes crossed by the rot, length of infection and percent lodging were common across two locations. These QTLs, consistent over environments for the component traits, are likely to assist in marker-assisted selection (MAS) for charcoal rot resistance in sorghum.     

The genetics of resistance in sunflower capitula to Sclerotinia sclerotiorum measured by mycelium infections combined with ascospore tests

To enhance efficiency of breeding programmes for Sclerotinia sclerotiorum resistance in sunflower capitula, two separate resistance tests have been recommended. However, the time necessary to develop genotypes with two types of resistance makes this impractical. A strategy to combine the two tests was consequently proposed to reduce the number of seasons per selection cycle, but genetic studies were necessary to determine if it could be applied in breeding programmes. This was the objective of this work. Data from two genetically different sunflower inbred lines and their F1, F2 and backcross generations were analysed in two years to determine the genetics of resistance to S. sclerotiorum in capitula measured by application on the same plants of a mycelium test combined with an ascospore test. Effects of maternal origin were detected when the reciprocal generations were evaluated for the mycelium test. This suggests the importance of choice of the inbred line used as female in population formation by hybridisation. Progeny subjected to the mycelium test did not show any change in relative reactions to two S. sclerotiorum isolates suggesting that ranking genotypes according to the results of combined S. sclerotiorum tests is repeatable across Sclerotinia isolates and experimental seasons. Moderate narrow sense heritability indicated that selection of the best F2 plants should be effective. Genetic gain from selection is possible because a reduction of lesion areas produced by the mycelium test can be expected. Additive gene effects contribute significantly to reduction in lesion area. Consequences of results in population improvement for S. sclerotiorum resistance in capitula are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

The inheritance and biochemistry of resistance to Sclerotinia sclerotiorum leaf infections in sunflower (Helianthus annuus L.)

Summary Resistance of sunflower leaves to attack by Sclerotinia sclerotiorum was studied by infecting them, in the field, with agar disks containing Sclerotinia mycelium. Resistance levels were determined by the length of lesions after a given period. There were significant differences in reaction between both sunflower hybrids and inbred lines. Different Sclerotinia isolates gave the same classification of sunflower genotypes. The results of trials repeated in one year or different years were significantly correlated. The general combining ability variance/specific combining ability variance ratio was 1.35. Strict sense heritability was 0.61±0.03. The midparent-offspring correlation coefficient was significant, but the relation between per se values of the male parents used with the values of their hybrids was much closer than that for the female parents. Mean heterosis for resistance was 28.9%, compared with the midparent. The results of the leaf resistance test are frequently correlated with levels of resistance to root attack by Sclerotinia. Possible use of this test in breeding both directly for leaf resistance and indirectly for root resistance are discussed. H.P.L. Chromatography studies of the phenols present in healthy and infected leaves distinguished 19 compounds, all of the inhibitin type. There was a large increase in phenol content in leaves infected by Sclerotinia, for all genotypes. However, more especially in uninfected leaves, the contents of 3 chromatogram peaks, numbered 4, 6 and 9, showed a close relation with levels of Sclerotinia resistance. It is proposed that these compounds could be used as markers of certain types of resistance.     

Genotype × environment interactions in the expression of net blotch resistance in spring and winter barley varieties

The net blotch resistance of barley varieties widely grown in Denmark was studied using data obtained from naturally infected field plots and inoculated disease nurseries in multiple years and locations. Data were analysed by combining two statistical procedures, 1) joint regression (JR) and 2) additive main effect, multiplicative interactive effect analysis (AMMI). Of the total variation for net blotch disease severity, 61–81% could be explained by plant genotype (G) and environment (E) main effects. Of the remaining variation, 77–86% could be explained by significant G × E interactions that were due to genotype sensitivity to the mean environmental disease level and/or to specific reactions of individual genotypes in particular environments. G × E interactions led to a different ranking of varietal performance across environments. There was evidence for G × E interactions caused by the virulence characteristics of the initial inoculum sources. The spring barley varieties Alexis and Bartok and the winter barley varieties Jolante, Ludo, and Rafiki were identified as varieties with high levels of net blotch resistance in all environments. Their performance was little affected by G × E interactions, suggesting that they represent good sources for non-specific resistance. Combining JR and AMMI reduced the dimensionality of complex G × E problems greatly, identified systematic reaction patterns of varieties possibly pertaining to different resistance mechanisms, and described specific and non-specific resistance of varieties by means of few parameters while maintaining the possibility to reconstruct the original data with little loss of information. This is very useful for improving the evaluation of varietal resistance for breeding and disease management purposes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hybrid breeding for fall armyworm resistance: Combining ability and hybrid prediction

Fall armyworm (FAW, Spodoptera frugiperda) emerged as a major lepidopteran pest destroying maize in sub-Saharan Africa. A diallel mating design was used to generate 210 experimental hybrids from 21 lines. Experimental hybrids and four checks were evaluated in two locations. Commercial checks suffered higher foliar and ear damage compared to the top 15 hybrids. Mean squares associated with the genotypic variation were higher than genotype-by-environment interactions for foliar and ear damage traits. Heritabilities were moderate to high. Significant correlations were observed between grain yield (GY) with ear rot (−0.54) and ear damage (−0.45). Positive and significant GCA effects were observed for GY in seven parental lines, which were developed from multiple insect resistance breeding programmes. CKSBL10153 has the highest GCA value for GY and shows significant GCA effects for foliar and ear damage traits. These lines were identified as the ideal combiners for GY and FAW resistance and are therefore recommended for utilization as testers in the development of FAW-resistant three-way cross-hybrid maize with correlated response for increased GY. GCA and marker-based prediction correlations of GY were 0.79 and 0.96, respectively. Both GCA effects and marker-based models were effective in predicting hybrid performance for FAW resistance.     

Resistance of sunflower inbred lines to various forms of attack by Sclerotinia sclerotiorum and relations with some morphological characters

Summary Twenty sunflower inbred lines were studied for their reactions to 7 Sclerotinia sclerotiorum tests on different plant parts. A principal component analysis (P.C.A.) and t-tests on the means of resistant and susceptible groups indicated that reactions of inbred lines to infection of capitula by ascospores are independent from those to ascospore infections of terminal buds. They are even more contrasted with the results of any test measuring mycelial extension. However, for the last, there is a close association between the reactions of roots, leaves and capitula. Of the inbred lines, some showed good levels of resistance to most forms of attack, others were generally susceptible and there were some with good resistance to one particular form of attack. A P.C.A. of 18 morphological and field characters showed no general association between these characters and Sclerotinia sclerotiorum test results, although it was found that lines resistant to mycelial extension on capitula were generally earlier than those that were more susceptible. It is proposed that breeding programmes for general resistance to Sclerotinia sclerotiorum should include a combination of two or three tests.     

Genetic analysis and genotype × environment (G × E) for grey leaf spot disease resistance in elite African maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) germplasm

Maize grey leaf spot (GLS) disease remains an important foliar disease in sub-Saharan Africa accounting for more than 25% yield losses in maize. Information on inheritance of GLS resistance of germplasm adapted to African environments is required in new sources being identified. Therefore, hybrids generated from a 10 × 10 half-diallel mating of tropical advanced maize inbred lines were evaluated in six environments to determine combining ability, genotype × environment interaction (G × E) and the impact of GLS disease on grain yield. General combining ability effects were highly significant and accounted for 72 and 68% of the variation for GLS resistance and grain yield, respectively. Significant specific combining ability effects associated with reduced disease levels were observed in some hybrids when one parent was resistant, and these may be exploited in developing single cross maize hybrids. Regression analysis showed a 260–320 kg ha^?1 decrease in maize grain yield per each increase in GLS disease severity score, and significant associations (r = ?0.31 to ?0.60) were observed between grain yield and GLS severity scores. This showed the potential of GLS disease to reduce yield in susceptible varieties grown under favourable disease conditions, without control measures. Genotype and genotype × environment biplots and correlation analysis indicated that the significant G × E observed was not due to changes in hybrid ranking, implying absence of a significant crossover interaction. Therefore, predominance of additive gene effects imply that breeding progress for GLS disease resistance would be made through selection and this could be achieved at a few hot-spot sites, such as Baynesfield and Cedara locations in South Africa, and still deploy the resistant germplasm to other environments in which they are adapted.     

Inheritance of several sources of resistance to Phomopsis stem canker (Diaporthe helianthi Munt.-Cvet.) in sunflower (Helianthus annuus L.)

The hybrids from 2 factorial crosses involving a total of 7 female lines and 11 restorers, representing the known range of reaction of sunflower to Phomopsis stem canker and most of the resistance sources used in breeding programmes, were studied in multilocational semi-natural attack trials and by artificial infections on leaves and stems in 1996, 1997 and 1998. The results confirm that resistance is quantitative, with predominantly additive effects, although there were some female × male interactions when individual trials were analysed. For lines used in both crosses, relative general combining abilities were stable. Some lines not bred for Phomopsis resistance showed good or intermediate levels of resistance. Lines from or including Yugoslavian, Rumanian and Russian sources of resistance and interspecific hybrids all provided good levels of resistance. The majority of parental lines showed the same relative reactions to semi-natural attack and artificial infections on leaves or stems indicating that their resistance is characterised by a slow rate of mycelial extension. However, one genotype showed resistance to passage of Phomopsis stem canker from the petiole to the stem and two genotypes appeared susceptible to tests but resistant to semi-natural attack, indicating that their resistance is controlled by factors not measured by the mycelium tests. The use of combinations of these resistance sources to give high levels of stable resistance to Phomopsis stem canker is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding for Sclerotinia resistance in sunflower: A modified screening test and assessment of genetic variation in current germplasm

Sclerotinia sclerotiorum (Lib.) de Bary is one of the most devastating pathogens of sunflower (Helianthus annuus), causing yield losses up to 100%. This study was conducted to (1) screen sunflower lines for their reaction to Sclerotinia using artificial infection by a modified leaf test, and (2) identify the most suitable trait for screening against Sclerotinia resistance. A set of 85 inbred lines was screened in three environments by infecting the leaves with mycelium and covering them with plastic bags containing water. Susceptibility was assessed by leaf lesion, petiole score, stem rating, stem lesion and diseased stems. The test proved to be effective and practicable, with an infection rate of up to 99%. All scoring traits were strongly correlated with each other and effective in differentiating among susceptible and resistant lines. Although petiole score had the highest heritability, its association with leaf length hampers its utilization as a scoring trait. Stem lesion was a good predictor of mid-stalk rot and can be recommended as a reliable trait for screening sunflower lines against Sclerotinia based on its high heritability estimate (h²= 0.59) and close correlations with other traits measured after artificial and natural infection.     

Inheritance of resistance to phomopsis (Diaporthe helianthi) in sunflower

The inheritance of resistance of sunflower to phomopsis (Diaporthe helianthi) was studied on 10 inbred lines representing a range of resistance and susceptibility levels, and 25 hybrids from a factorial cross of these lines. Analyses of observations over a 3-year period, of semi-natural infection (presence of stem lesions greater than 5 cm) on the hybrids indicated that additive gene control was predominant, with no significant interactions between parental effects. Correlations between infection of parental lines and the mean of their hybrids were not always significant, with certain inbreds which appeared quite susceptible giving hybrids with good levels of resistance. In order to predict hybrid values, it appears necessary to determine the general combining abilities of parental lines. Some inbreds gave very high levels of resistance, others gave very high levels of susceptibility. A test measuring the rate of extension of D. helianthi mycelium on leaves was significantly correlated with the results of natural infections. In particular, it permitted distinction of the most susceptible genotypes, and thus could be used in first generations of breeding to eliminate the most susceptible plants.     

Accumulation of soluble phenolic compounds in sunflower capitula correlates with resistance to Sclerotinia sclerotiorum

Disease symptoms and total soluble phenolics content have been analysed in four sunflower (Helianthus annuus L.)lines with different resistance levels(from highly susceptible to resistant) to head rot caused by Sclerotinia sclerotiorum (Lib.) de Bary. At the beginning of the flowering stage, capitula were inoculated by spraying with a water suspension of ascospores, and disease symptoms were evaluated from day 6 to day14 after inoculation. The most susceptible genotypes showed all their ovaries to be necrosed and abundant lesions in corollas, bracts and receptacle. In the resistant line, the ovary and corolla were only partially necrosed with no symptoms in the bracts or the receptacle. Total soluble phenolics were extracted and quantified from different parts of the capitulum in both inoculated and non-inoculated plants. The amount of phenolic compounds depended on the sunflower line, the time after inoculation, and the tissue. Higher constitutive and induced phenolic content as well as phenylalanine ammonia-lyase activity were present in the most resistant line, these differences correlated with the absence/presence of disease symptoms. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inheritance of White Rust Resistance in Brassica juncea

Inheritance of white rust resistance was studied in two crosses between resistant (R) and sensitive (S) types of Brassica juncea, namely EC 12749 בParkash’ (R × S) and EC 12749 בVaruna’ (R × S) under conditions of normal and late sowing. Analysis of six generations revealed the importance of additive, dominant and epistatic effects. Disease was more prevalent under late sowing due to favourable environment. Reciprocal recurrent selection is advocated for exploiting the additive and non-additive gene effects for resistance to white rust.     

Comparative genotype reactions to Sclerotinia sclerotiorum within breeding populations of Brassica napus and B. juncea from India and China

Twenty Brassica breeding populations derived from mass selection or inter-specific hybridization were field screened for resistance to three separate isolates of Sclerotinia sclerotiorum, the cause of Sclerotinia stem rot (SSR). Variation due to S. sclerotiorum isolates (P ≤ 0.001) and host populations (P ≤ 0.001) were highly significant. Populations × isolate interactions were also significant. S. sclerotiorum isolates, MBRS1 and MBRS5 were the most pathogenic and almost similar in terms of population reactions, with WW3 clearly being distinct and having a much smaller range in lesion length across the populations. There were wide ranging and variable responses in terms of resistance against S. sclerotiorum in Brassica napus and B. juncea, with or without B. carinata introgression, among these breeding populations. In B napus, ZY006 (resistant check) and Line6 (HZAU) were the most resistant, closely followed by Line1 (HZAU), OCRI-3 and Line5 (HZAU). Line6 (HZAU) showed excellent resistance against the highly virulent isolates MBRS1 and MBRS5; while OCRI-1 appeared most resistant against isolate WW3. The B. juncea × B. carinata hybrid JC134 (PAU) was the most resistant against isolate MBRS5 and B. juncea RH9902 × JN026 the most resistant against isolate MBRS1. B. napus lines Line2 (HZAU), Line4 (HZAU), OCRI-3; and OCRI-4, and the B. napus × B. carinata hybrid Surpass4000 NCB4 (PAU), showed a significant degree of isolate-dependency in their reactions. In contrast, some other genotypes such as B. napus lines Line1 (HZAU), OCRI-5; Ding 110× Oscar and, particularly, Line5 (HZAU), were largely isolate-independent, making them ideal sources of resistance to target and exploit in developing new commercial cultivars with more effective resistance to SSR across multiple pathotypes of this pathogen. Cluster analysis allowed categorization of the test populations into five groups, based on their resistant responses. B. napus ZY006 was the sole genotype in the most resistant group. B. napus lines Line6 (HZAU), Ding 110 × Oscar (HAU) and Line4 (HZAU) clustered in another genetically distinct resistant group. That lines could be grouped into those with similar responses across the three different isolates of S. sclerotiorum will save breeders much time and expense by eliminating duplication of breeding efforts that occurs from using genotypes that are essentially similar in terms of host resistance against this serious pathogen. Further, that populations of similar levels of resistance but narrow variation in the resistance range could be identified is significant, as these are most likely to reliably provide breeders with advanced populations that not only consistently display the level of resistance expected but also reflect genetic diversity of resistance sources needed to successfully develop new more-resistant commercial varieties.     

Relationship between European corn borer resistance and concentration of mycotoxins produced by Fusarium spp. in grains of transgenic Bt maize hybrids, their isogenic counterparts, and commercial varieties

The European corn borer (ECB), Ostrinia nubilalis Hb., is a major pest of maize in central Europe and promotes the infection of maize with Fusarium spp. In this study, transgenic Bt maize hybrids were compared with their isogenic counterparts, and with commercial hybrids from the recommended list with regard to their level of ECB resistance and their concentration of deoxynivalenol (DON), its 15‐acetyl (15‐A‐DON) and 3‐acetyl (3‐A‐DON) derivatives, nivalenol (NIV), fusarenon‐X (FUS‐X), fumonisins (FUM), and zearalenon (ZEN) in harvested grains. The field experiments were performed in Germany at four locations in 1999 and at five locations in 2000. Transgenic Bt hybrids showed significantly lower means than their corresponding isogenic counterparts and than commercial hybrids for all resistance traits: damage rating of stalks, number of larvae per plant, number of larvae per ear, and percentage of damaged plants or ears under infestation. Among all mycotoxins analysed, DON consistently showed the highest concentration across all year × location combinations. Mycotoxin concentrations varied significantly between locations, years and genotypes, whereas mycotoxin concentrations were not significantly different between infested and protected plots. Associations between ECB resistance traits and mycotoxin concentrations were not consistent across years. It is concluded that under central European conditions, the use of Bt maize hybrids will only slightly reduce the contamination of maize kernels with mycotoxins produced by Fusarium spp.     

Identification of resistant sources against <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis> in <Emphasis Type="Italic">Brassica</Emphasis> species with emphasis on <Emphasis Type="Italic">B. oleracea</Emphasis>

Stem rot caused by Sclerotinia sclerotiorum is one of the most devastating diseases of rapeseed (Brassica napus L.) which causes huge loss in rapeseed production. Genetic sources with high level of resistance has not been found in rapeseed. In this study, 68 accessions in six Brassica species, including 47 accessions of B. oleracea, were evaluated for leaf and stem resistance to S. sclerotiorum. Large variation of resistance was found in Brassica, with maximum differences of 5- and 57-folds in leaf and stem resistance respectively. B. oleracea, especially its wild types such as B. rupestris, B. incana, B. insularis, and B. villosa showed high level of resistance. Our data suggest that wild types of B. oleracea possess tremendous potential for improving S. sclerotiorum resistance of rapeseed.     

Meiosis and pollen grain viability in Helianthus mollis,Helianthus salicifolius,Helianthus maximiliani and their F1 hybrids with cultivated sunflower

Three diploid perennial sunflower species are useful for variety improvement: Helianthus mollis, because of sessile leaves, H. salicifolius, because of a high oil concentration, and H. maximiliani, a potential source of resistance to Sclerotinia sclerotiorum. The crossability of these species to cultivated sunflower was examined.Hybrids were obtained from eight combinations, with 3–15 F₁ plants per combination. The F₁'s exhibited the dominant phenotype of the wild species. Pollen viability varied between 32.1 and 69.9%. Meiosis was irregular in the F₁ hybrids. At diakinesis, bivalents (62.7–97.9% of meiocytes), univalents (0–31.23%), and multivalents (3.84–7.68%) were detected. At anaphase I, chromosome bridges were detected in 6.77 to 11.44% of meiocytes. Fast chromosomes in metaphase I, and lagging chromosomes in anaphase I and telophase II were evidenced in a high percentage of meiocytes.