Seed dormancy and dormancy‐breaking methods in Leymus chinensis (Trin.) Tzvel. (Poaceae)

Leymus chinensis (Trin.) Tzvel. is a perennial grass with high productivity and forage value; however, poor stand establishment, often due to seed dormancy, limits its widespread use for forage production. To investigate the mechanism of seed dormancy and to develop effective methods of improving germination, the contribution of each part of the caryopsis to dormancy was investigated, and a number of single or combined dormancy‐breaking pre‐treatments were conducted using three seed lots. The palea, lemma, pericarp/testa, and endosperm all contributed to seed dormancy. The contribution of each part to dormancy was 23·4%, lemma; 6·2%, palea; 28·4%, pericarp/testa; and 42·0%, endosperm. Hull (palea and lemma) removal, pericarp/testa piercing, and soaking in distilled water or 30% sodium hydroxide (NaOH) significantly decreased the percentage of dormant seeds (i.e. increased germination). Treating hull‐removed and pericarp/testa‐pierced seeds with gibberellic acid (GA₃) also significantly decreased the percentage of dormant seeds. Compared with each of the single pre‐treatments, the combined pre‐treatment of pre‐soaking in water for 1 d, then 30% NaOH for 60 min and treating with 300 μm GA₃ resulted in the highest germination (89%); and seed viability was 91%.     

Changes in soil organic carbon pools in a long‐term trial with perennial fodder crops in acid soils of north‐east India

Efficient estimation of soil organic carbon (SOC) is vital for understanding and monitoring the effect of perennial fodder crops in conserving SOC. In subtropical regions, there is limited information on SOC accumulation and its allocation into different pools under long‐term grasses and legumes. Therefore, we investigated the dynamics of SOC in a 20‐year‐old field trial with seven perennial grass species and a legume in a Typic Paleudalf soil under subtropical climate in north‐east India by analysing oxidizable organic C (C_oc) and its fractions of very labile (C_VL), labile (C_L), less labile (C_LL) and non‐labile (C_NL), microbial biomass C (C_mic) and mineralizable C (C_min). Growing perennial fodder crops increased SOC in the 0–0.60 m soil depth from 19.9%–39.6% compared with the conventional cultivation with maize (Zea mays). The relative efficacy of the fodder species to SOC accumulation was Setaria sphacelata = Brachieria rosenesis > Panicum maximum cv. Makunia = Arachis pintoi > Panicum maximum cv. Hamil > Paspalam conjugalum = Pennisetum purpureum > Thysanolaena maxima. Among the analysed fractions, C_VL, C_L, C_LL and C_mic were influenced most by the fodder crops and the active pools (C_VL+C_L) constituted 71.6% of the SOC. The results indicate that under the tested subtropical climate, soil under perennial grasses and legumes conserves organic C and that most of the SOC is in labile pools of short residence time.     

Variability in germination behaviour of Paspalum dilatatum Poir. seeds is genotype dependent

Dallisgrass (Paspalum dilatatum Poir.) is a warm‐season grass, native to South America. Its adoption as a pasture crop has been hindered by low seed germination and slow establishment. However, variability in germination behaviour for this species has never been systematically analysed. For Paspalum spp., dry‐storage and moist cold or warm pre‐conditioning treatments have been reported as effective for the relief or breaking of seed dormancy. In the present work, seed germination responses at 32°C were assayed for sixteen P. dilatatum genotypes, representing its known natural genetic variability, to two moist pre‐conditioning treatments (at 5 and 20°C) and without pre‐conditioning, and three seed storage periods (0, 3 and 6 months). Pre‐conditioning at 20°C showed high germination percentages (>80%), with ratios equal to or higher than pre‐conditioning at 5°C, suggesting that cold is not required to break dormancy. Longer storage times resulted in increases in germination responses for most of the genotypes, while other biotypes showed no effect. Biotypes Virasoro and Chirú showed a remarkably different behaviour with higher germination percentages of untreated freshly harvested seeds. Our results show that diversity for traits involved in seed germination exists among naturally occurring P. dilatatum genotypes and the characterization of these traits should be addressed during ecotype characterization and evaluation of potential domesticates of this species.     

Hormonal Mechanisms of Dormancy Induction in Developing Seeds

Summary

Primary dormancy develops in seeds during their maturation on the mother plant. In recent years, the use of hormone mutants and the manipulation of endogenous hormone levels by their biosynthetic inhibitors have led to a new approach of the hormonal regulation of the onset of dormancy. There is good evidence to show that ABA synthesis at axis level is an absolute requirement for the induction and maintenance of dormancy. This continued de novo synthesized ABA could positively control the expression of specific ABA-responsive genes. Among the set of late embryo abundant proteins, some appear to be good candidates as “dormancy proteins.” This review aims to correlate the preliminary results obtained by molecular biology with the recent advances in understanding the hormonal control of dormancy induction in developing seeds.     

Long‐term storage of forage legumes greatly alters the hard seed breakdown pattern in situ

Knowledge of the hard seed content of annual legumes, and its pattern of breakdown, is critical to the understanding of their ecology and management within farming and natural ecosystems. For logistical reasons, seed that has been stored for varying lengths of time is often used for pasture establishment and agronomy experiments. However, the implications of storage on hard seed physiology are unknown. The aim of this study was to explore the impact of seed storage on its subsequent pattern of hard seed breakdown when exposed to field conditions. Experiments examined seed from six different annual legume cultivars that had been either produced the prior year or stored under ambient conditions for 11–22 years. Comparisons were then made between the two seed sources on hard seed breakdown patterns in situ. Although initial hard seed levels were mostly unaffected by storage (seed of five cultivars remained over 93% hard after more than 11 years of storage), the patterns of release from dormancy during exposure to hard seed breakdown conditions of stored seed differed greatly (p < .05) from freshly produced seed. Hard seed in the stored seed of most cultivars was reduced from >90% to <10% within 68 days over autumn, with shallow burial, whereas fresh seed remained >90% hard during the same period. Given this large and consistent impact, it is recommended that studies of the patterns of hard seed breakdown in legumes compare seed stored under consistent and well‐defined conditions.     

Vicia villosa ssp. villosa Roth field emergence model in a semiarid agroecosystem

Hairy vetch (Vicia villosa Roth) is a winter annual legume cultivated for pasture and hay with the capability for natural reseeding. Vicia villosa increases N concentrations in the soil, thus contributing to the sustainability of semiarid regions. However, under rotations of 1–2 years of pasture followed by 1 year of crop (1:1–2:1), hairy vetch could become a problematic volunteer weed in the winter cereal crop phase. This study aimed to develop a mechanistic model for hairy vetch seedling emergence in order to (i) estimate the natural reseeding of hairy vetch in the pasture phase of the field rotation, or (ii) develop control strategies considering hairy vetch as a volunteer weed in the winter cereal phase. The proposed model simulates the pattern of field emergence of hairy vetch after natural seed dispersal by integrating four submodels: (i) physical (PY) dormancy release dynamics, (ii) physiological dormancy (PD) release and germination thermal requirements, (iii) hydro‐time requirements for germination, and (iv) pre‐emergence growth respectively. The developed field emergence model was validated with independent field emergence data during 2013, 2014 and 2015. The model adequately predicted the timing and magnitude of field emergence flushes (RMSE < 10.1) despite the environmental variability among years. The additive effect of each submodel clearly improved the explanatory capacity of the field emergence patterns. The alleviation of PD synchronizes the timing for hairy vetch germination, while the PY determines the seedbank persistence. These outcomes suggest the potential applicability of the proposed modelling approach within management decision support systems.     

Soil water dynamics,herbage production and water use efficiency of three tropical grasses: Implications for use in a variable summer‐dominant rainfall environment,Australia

In the moist mid‐latitudes of eastern Australia, soil water dynamics, herbage production and water use efficiency (WUE) were monitored during 2006–2008, for five perennial pastures: digit grass (Digitaria eriantha), Rhodes grass (Chloris gayana), forest bluegrass (Bothriochloa bladhii), native grass (Bothriochloa macra and Rytidosperma bipartita dominant), lucerne (Medicago sativa); and two forage crops: oat (Avena fatua) and sorghum (Sorghum bicolor). Ground cover formed more quickly in Rhodes grass and lucerne (>70% ground cover in 120 and 175 days after sowing [DAS] respectively) than in forest bluegrass and digit grass (245 and 365 DAS respectively). Values of maximum extractable water (MEW) for Rhodes grass and lucerne were similar (180–242 mm), while values for digit grass and forest bluegrass (129–175 mm) were equal to or greater than those for native grass, and two annual forage crops (77–144 mm). Lucerne expressed the maximum root depth (1.46 m), while values for the tropical grasses (0.96–1.39 m) were greater than native grasses and forage crops (0.87–0.96 m). Native grasses (6.5–12 t DM/ha) had the lowest herbage production, which resulted in values of WUE that were significantly less than most other treatments (16–21 vs. 23–43 kg DM ha^?1 mm^?1). Digit grass (33–34 kg DM ha^?1 mm^?1) had higher WUE compared with the other tropical grasses (20–27 kg DM ha^?1 mm^?1). The data collected here suggest that a forage system comprising digit grass, lucerne and forage oat would provide high production and WUE in this environment.     

Simulating bimodal tall fescue growth with a degree‐day‐based process‐oriented plant model

Plant growth simulation models have a temperature response function driving development, with a base temperature and an optimum temperature defined. Such models function well when plant development rate shows a continuous change throughout the growing season. This approach becomes more complex as it is extended to cool‐season perennial grasses with a dormant period and bimodal growth curves. The objective of this study was to develop such a bimodal growth model for tall fescue (Schedonorus arundinaceus (Schreb.) Dumort) in the Midwest USA based on multiyear measurement trials. Functions for bimodal growth were incorporated into the ALMANAC model and applied to tall fescue using published tall fescue yields for a variety of sites and soils. Fields of cultivars “Kentucky 31” and “BarOptima Plus E34” were divided into paddocks and sampled weekly for dry‐matter accumulation. These biomass estimates were used to derive weekly growth values by differences between sequential weekly samplings. The measured values were compared to a single tall fescue simulation each year on one soil. Using these results, the ALMANAC model was modified and tested against mean reported tall fescue yields for 11 sites, with one to three soils per site. When we introduced midsummer dormancy into ALMANAC, we assumed dormancy began on the longest day of the year and lasted until the photoperiod was 0.68 hr shorter than the longest. ALMANAC simulated previously reported tall fescue yields well across the range of sites. Thus, ALMANAC shows great promise to simulate bimodal growth in this common cool‐season grass.     

Breaking the dormancy of rice seeds with various dormancy levels using steam and high temperature treatments in a steam nursery cabinet

This study aimed to determine the appropriate steam treatment conditions, using a steam nursery cabinet, to break the dormancy of Japanese rice cultivar seeds exhibiting various dormancy levels. The influence of the temperature and duration of the steam treatments on the germination percentage and germination rate was investigated. In highly dormant ‘Takanari’ seeds, the steam treatment at 40 °C for 7 d increased the germination percentage and decreased the 50% germination time (T_50S; based on seed number); this treatment was as effective as the dry heat treatment at 50 °C for 7 d. For the medium dormant ‘Moeminori’ and ‘Hitomebore’ seeds, the steam treatment at 40 °C for 5 d decreased T_50S sufficiently and more effectively than did the dry heat treatment at 50 °C for 7 d. For the slightly dormant ‘Moeminori’ seeds, the steam treatment at temperatures ranging from 24 °C to 40 °C for 7 d decreased T_50S without a corresponding decrease in germination percentage to <90%. For the non-dormant ‘Moeminori’ and ‘Takanari’ seeds, the same steam treatments had no, or a little if any, useful effect on the germination percentage and T_50S. Therefore, we concluded that, for the highly dormant seeds, steam treatment at 40 °C for 7 d was appropriate. Moreover, for less dormant seeds, steam treatment at 40 °C for 5 d was appropriate, and the steam treatment was not necessary for the non-dormant seeds.     

Effect of ascorbic acid on seed germination of three halophytic grass species under saline conditions

Grasses on the Pakistani coast are moderately to highly salt tolerant and have potential for utilization as a cash crop. This study was designed to determine whether seed germination of three halophytic grasses (Phragmites karka, Dichanthium annulatum and Eragrostis ciliaris) could be improved by exogenous application of ascorbic acid (AsA) under saline conditions. Seeds of P. karka were germinated in varying concentrations of NaCl and AsA under different temperature regimes, and seeds of Dichanthium annulatum and Eragrostis ciliaris were germinated at optimal temperatures only. In P. karka, concentrations of AsA (5 and 10 mM) alleviated the salinity effects better at cooler and moderate thermo‐periods, whereas higher concentrations (20 mM of AsA) failed to improve germination under all temperature regimes. AsA was ineffective at a warmer thermo‐period (25/35°C). The rate of germination also increased at all thermo‐periods with the application of AsA except at 25/35°C under saline conditions. Application of AsA improved the germination of E. ciliaris seeds under saline conditions but was inhibitory for D. annulatum in comparison with the untreated control. The rate of germination followed the similar pattern as that of seed germination. Results indicate that AsA has the ability to partially alleviate the effect of salinity on seed germination of some grass species under optimal temperature regime.     

Cultivation offers effective management of subterranean clover damping‐off and root disease

Soil cultivation studies involving subterranean clover pastures were undertaken utilizing field cores from five farms and two in‐field trials. Tap and lateral root disease in cores was less (p < .001) severe and root and shoot weights greater (p < .001) following simulated cultivation. Germination and severity of root disease were both affected (p < .005) by three‐way interactions with cultivation, cultivar and field site. Cultivation in cores suppressed tap root disease for cultivars Meteora and Riverina across the five sites and Seaton Park for two sites. In‐field trials confirmed cultivation reduces root disease severity and increases germination and plant productivity. The best in‐field treatment was cultivation + fumigation that reduced (p < .05) tap and lateral root disease and increased nodulation and root and shoot weights for Riverina, Seaton Park and Woogenellup. Cultivation + fumigation also increased (p < .05) germination for Woogenellup and Seaton Park. There were negative correlations (all p < .001) between tap and lateral root disease with nodulation (R² = .85, R² = .58, respectively); tap root disease with root and shoot weight (R² = .58, R² = .854, respectively); and lateral root disease with root and shoot weight (R² = .83, R² = .64 respectively). This study highlights the close relationship between severe root disease and reduced nodulation, likely explaining much of the widespread poor nodulation in subterranean clover pastures. This study confirms that damping‐off and root disease can be mitigated by cultivation, offering producers flexibility in disease management, especially where autumn–winter feed shortages occur on a regular basis.     

Identification,ecological evaluation and phylogenetic analysis of non‐symbiotic endophytic fungi colonizing timothy grass and perennial ryegrass grown in adjacent plots

Non‐systemic endophytes coexist with grasses and produce positive or negative effects for the host. In agricultural grasses, endophytes such as Epichloë spp. (formerly: Neotyphodium spp.) enhance the biometric parameters and agricultural value of grass biomass and seeds. Some endophytic fungi produce active substances that exert a negative influence on grass‐fed livestock. There is a general scarcity of studies investigating other endophytic fungi, the species composition of fungal communities, fungal species capable of colonizing different grasses and endophyte transfer between grass taxa. This study aims to fill in the existing knowledge gap by describing the relationships between fungal species and grass species. Timothy grass (Phleum pratense L.) is more readily colonized by endophytic fungi than perennial ryegrass (Lolium perenne L.), and the ratio of fungi isolated from the above species was determined at 3:1. Ecological indicators, especially diversity, were also higher in the fungal community colonizing timothy grass. The vast majority of the isolated fungi were ascomycetes. In addition, two Basidiomycota isolates and three Oomycota isolates (Phythium acanthicum) were also obtained from timothy grass. The most prevalent fungal species were Alternaria alternata, Microdochium bolleyi and Epicoccum nigrum. An analysis of minisatellite DNA regions revealed high levels of genetic polymorphism in A. alternata, whereas the remaining isolates were characterized by low levels of genetic variation or genetic homogeneity. The transfer of endophytic fungi between grass species was determined, which was one of the most important observations made in the study. The Sørensen–Dice coefficient reached 50%, which indicates that all fungal species isolated from perennial ryegrass are capable of colonizing timothy grass.     

Tensile fracture properties of seven tropical grasses at different phenological stages

The intake of forage grasses by grazing ruminants is closely related to the mechanical fracture properties of grasses. The relationship between the tensile fracture properties of grasses and foraging behaviour is of particular importance in tropical reproductive swards composed of both stems and leaves. This study (i) quantified and compared the tensile fracture properties of stems and leaves of seven tropical grass species and (ii) provided insight into the underlying plant traits that explain differences in fracture properties between species. Fracture force, tensile strength, fracture energy and toughness of stems (in various phenological stages) and leaves were measured and compared among five introduced tropical grasses (Cenchrus ciliaris, Chloris gayana, Digitaria milanjiana, Megathyrsus maximus (syn. Panicum maximum), Setaria sphacelata) and two native tropical grasses (Setaria surgens and Dichanthium sericeum). Species differed significantly in fracture force and fracture energy, with stems and leaves of C. ciliaris and S. surgens requiring less force and energy to fracture and stems and leaves of M. maximus and S. sphacelata requiring more force and energy to fracture in comparison with the other species. Differences in tensile strength and toughness were less pronounced. The differences among species in fracture force and energy mainly resulted from differences in cross‐sectional area of plant parts rather than from differences in tensile strength and toughness.     

Seed production in grassland species: Morpho‐biological determinants in a species‐rich semi‐natural grassland

Studying the seed production of herbaceous species can help to conserve grassland habitats and re‐create new high‐value grassland surfaces. Studies on grassland seed production have focused mainly on individual species and traits, without characterizing their relative importance at the plant community level. The aim of this study was to investigate the entire seed production process of the main species in a temperate grassland. Fertile shoots (FS) of twenty‐nine grasses and forbs were collected over 4 years and analysed for sixteen traits that determine inflorescence size, seed production and seed quality. The per cent viability played a predominant role in determining the total production of viable seeds. Forbs showed a range of reproductive strategies, including variable distribution of flowers among growth periods, number of inflorescences per FS and relationship between seed size and FS density in the grassland. The flower production for grasses was concentrated in the first growth period, but this limitation was mitigated by a higher seed dormancy. The number of viable seeds per FS and seed size were important components of the reproductive strategy of forbs, with heavy‐seeded species being characterised by high individual densities in the community, but producing few seeds per FS. Light‐seeded species showed an opposite pattern. The results suggest that when using seeds from semi‐natural grasslands for ecological restoration, special attention should be paid to the seed amount, germinability and viability of forbs, as they seem to depend more on seed reproduction and have a lower ovule to seed transformation efficiency.     

Confirmation of Novel Quantitative Trait Loci for Seed Dormancy at Different Ripening Stages in Rice

Seed dormancy contributes resistance to pre-harvest sprouting.Effects on respective quantitative trait loci (QTLs) for dormancy should be assessed by using fresh seeds before germinability altered through storage.We investigated QTLs related to seed dormancy using backcross inbred lines derived from a cross between Nipponbare and Kasalath.Four putative QTLs for seed dormancy were detected immediately after harvest using composite interval mapping.These putative QTLs were mapped near C1488 on chromosome 3 (qSD-3.1),R2171 on chromosome 6 (qSD-6.1),R1245 on chromosome 7 (qSD-7.1) and C488 on chromosome 10 (qSD-10.1).Kasalath alleles promoted dormancy for qSD-3.1,qSD-6.1 and qSD-7.1,and the respective proportions of phenotypic variation explained by each QTL were 12.9%,9.3% and 8.1%.We evaluated the seed dormancy harvested at different ripening stages during seed development using chromosome segment substitution lines (CSSLs) to confirm gene effects.The germination rates of CSSL27 and CSSL28 substituted with the region including qSD-6.1 were significantly lower than those of Nipponbare and other CSSLs at the late ripening stage.Therefore,qSD-6.1 is considered the most effective novel QTL for pre-harvest sprouting resistance among the QTLs detected in this study.     

青稞主效休眠基因单倍型分布及利用

穗发芽严重降低谷物的产量和品质,种子休眠与穗发芽高度相关。为了解中国青稞品种休眠特性及其主效休眠基因AlaAT和MKK3的单倍型分布,以143份地方品种和42份育成品种(系)为材料,分别种植在四川雅安、什邡和西藏拉萨,进行大田种子休眠性鉴定;选择休眠性极端材料,分别利用2对引物对含有目标休眠基因功能性SNP的片段进行扩增、测序,并用于AlaAT 和 MKK3基因特异性KASP标记开发与供试材料的单倍型分析。结果表明,3个种植点,地方品种的发芽指数（GI）均高于育成品种（系）,但差异不显著;四川2个种植点间GI值差异不显著,但显著高于西藏种植点,说明青稞品种（系）普遍休眠性弱,高原气候条件显著促进种子休眠。KASP标记检测发现,AlaAT 和 MKK3的强优势单倍型均为弱休眠单倍型 （频率>80%）,供试材料中有4种单倍型组合,分别为AlaAT-ND+MKK3-ND、 AlaAT-ND+MKK3-D、 AlaAT-D+MKK3-ND和AlaAT-D+MKK3-D,频率分别为80.0%、12.4%、6.0%和1.6%,其GI值随强休眠单倍型数量增加而降低;3个环境下,含有组合AlaAT-D+MKK3-D的GI值最低,说明休眠基因具有加性效应,聚合优良单倍型的品种（系）具有稳定的休眠特性。青稞生产和育种应根据种植区域和用途选择与利用上述主效休眠基因单倍型。     

Mice find endophyte‐infected seed of tall fescue unpalatable – implications for the aviation industry

Bird strike is a significant problem for the aviation industry, caused in part by the attractiveness of the grass surrounding airports to birds. Endophyte‐infected grasses such as Avanex^® have been shown to reduce bird populations at airports through the production of secondary metabolites. These metabolites are unpalatable to herbivorous, omnivorous and granivorous birds and are known to reduce insect densities, thereby making the sown areas less attractive to insectivorous birds. Raptors also provide a bird‐strike threat which could be reduced by controlling mouse populations around airports. In this study, the effect of endophyte‐infected seed on mouse feeding behaviour has been investigated. By performing a choice trial offering diets containing endophyte‐infected and endophyte‐free tall fescue seed, it was shown that endophyte‐infected seed was less palatable to mice (P < 0·001 in a 14‐d trial). Furthermore, when diet positions were reversed, mouse feeding behaviour was modified to again select endophyte‐free material (P < 0·001 over a further 14 d). This result shows that endophyte‐infected grasses could not only be used in the control of bird populations but they also have the potential to control mouse populations which in turn would decrease the number of raptors. This use of endophyte‐infected grasses in areas surrounding airport runways shows great promise for the aviation industry.     

Effect of storage temperature and extraction methods on dormancy and germination of true potato seed

Seed treatments, methods of extraction and storage temperature were examined for effects on viability and dormancy of true potato seed. Dormancy of 4x?2x (S. tuberosum ×S. phureja) hybrids was eliminated after 7 months at room temperature and after 10 months at 4 C. However, data on the velocity and uniformity of germination (coefficient of velocity) revealed the presence of a residual dormancy that persists for nearly two years in seeds stored at 4 C, but which is largely eliminated after one year in seeds stored at room temperature. Seed viability was not affected by blender extraction, although seed extracted by hand gave a significantly lower initial coefficient of velocity (CGV). Application of gibberellic acid (GA, 1000 ppm) as a 24-hour soak to freshly extracted seed eliminates dormancy as effectively as GA applied during germination, and produces no deleterious effects on seed viability up to two years in storage. There were genotypic differences for seed dormancy within the tetraploid and diploid groups examined. SeveralS. tuberosum cultivars displayed a dormancy effect (lower CGV’s) in fresh seed that was not completely eliminated by GA, but which declines over time in storage.     

云南铁壳麦的穗发芽抗性鉴定与分析

为了解云南铁壳麦(Triticum aestivum ssp.yunnanense)的穗发芽抗性及其机制、筛选抗性材料,以白粒推广良种云麦53号为对照,采用整穗发芽、整粒发芽及分子功能标记的方法,鉴定了55份云南铁壳麦的穗发芽抗性及种子的休眠特性,分析了发芽指数(germination index,GI)在穗发芽抗性级别不同的材料间、分子功能标记基因等位变异间的差异及籽粒发芽率(germination percent,GP)在不同休眠级别的材料间的差异。结果表明,以整穗发芽率(spikes germination rate,SGR)为鉴定指标,在对照云麦53号的SGR达76.2%的前提下,云南铁壳麦除1份材料SGR为2%外,其他材料的SGR都为0,与对照相比,对穗发芽的抗性都很强。以GI为鉴定指标,供试云南铁壳麦对穗发芽的抗性则较弱,抗性材料较少,GI为15.5%～72.8%(对照的GI为65.7%),GI在抗性级别不同的材料间明显不同。以籽粒发芽率为依据,云南铁壳麦的种子休眠性可分为休眠、中度休眠、浅休眠和无休眠4级,GP在不同休眠级别的材料间也显著不同。用STS功能标记 Vp1B3扩增出A带(652 bp)、C带(无带)的材料,其GI均与扩增出B带(569 bp)材料的GI有明显差异;用标记Vp1A3扩增出B带(170 bp)材料的GI与C带(无带)材料的GI也有明显差异,其他3个功能标记( Tasdr-B1、 Tamyb10D1、 Tamyb10D)扩增到不同带型材料的GI则无明显的不同,用分子标记获得的结果不能解释云南铁壳麦的穗发芽抗性或种子休眠特性的变化。