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1.
Summary The resistance of 19 cultivars of subterranean clover was screened against 4 races of P. clandestina by mycelial inoculation of roots of 10-day-old seedlings growing in water agar and by growing seedlings in pasteurised potting mix containing infested vermiculite in controlled conditions. The cultivars showed differential resistance (vertical resistance) to races of the pathogen and can be divided into 4 resistance groups. Cultivars Clare, Esperance, Green Range, Junee, Mount Barker, Rosedale, Woogenellup and Yarloop were susceptible to all races. Cultivars Bacchus Marsh, Denmark, Enfield, Gosse, Goulburn, Karridale, Larisa, Leura and Trikkala were susceptible to races 1 and 3, but resistant to races 0 and 2. Cultivar Meteora was susceptible to races 2 and 3, but resistant to races 0 and 1. Cultivar Seaton Park (LF) was resistant to all races. Cultivars also varied in their race-non-specific (horizontal) resistance: cultivars that were susceptible to particular races usually varied in their degree of susceptibility to those races. In particular, Junee was more resistant to all four races than the other cultivars within its group. Similarly, cultivars Gosse, Larisa, Denmark and Trikkala were more resistant to races 1 and 3 than the other cultivars in their group. Races of the pathogen varied in their aggressiveness as well as in their virulence, as shown by the variation in aggressiveness of different isolates of race 0. 相似文献
2.
Summary Interaction of six isolates of Kabatiella caulivora (545, 547, 2212, BNL, BDG and KLN) collected from different geographical regions of Western Australia and Victoria with six cultivars (Clare, Daliak, Enfield, Guildford D, Karridale and Woogenellup) of subterranean clover was studied at seedling (2-week old) and adult-plant (12-week old) stages. Seedling response measured as percentage of diseased plants showed cultivar Daliak to be immune to all isolates, while the remaining cultivar x isolate combinations showed differing degrees of susceptibility.The adult-plant response, measured as percentage of petioles affected per plant, showed that all the cultivars were susceptible to varying degrees to all the isolates, with Daliak being the most resistant cultivar.Analysis of variance of both seedling and adult-plant resistance showed significant (P<0.05) effects due to cultivars, isolates and their interaction. The magnitude of variance due to the isolates was substantially reduced when measured as adult-plant response. Leaf scorch severity was clearly influenced by cultivar and its developmental stage, and by isolate of the pathogen. 相似文献
3.
Use of resistant plant varieties combined with other disease management practices is regarded as the most practical approach to control of seed-borne bacterial disease agents. In this study, responses of different bean cultivars to nine different races of Pseudomonas syringae pv phaseolicola, the causal agent of bacterial halo blight of common bean (Phaseolus vulgaris L.), were determined. During compatible interaction in susceptible cultivars, virulent bacterial races caused water soaked lesion at sites of inoculation. Similar lesions developed in moderately resistant cultivars but symptoms were later associated with more tissue browning around the sites of inoculation. In contrast, the resistant response, produced the characteristic hypersensitive reaction (HR), was characterized as a small discrete browning and tissue collapse at site of inoculation. No local cultivars showed complete resistance to all races tested. Bean cultivars Sehirali-90 and Göynük-98 were found to be resistant or moderately resistant to five different bacterial races. Bean cultivar, Karaca?ehir-90, on the other hand, was found to be resistant or moderately resistant to six different bacterial races. Analysis of bacterial growth and the accumulation of isoflavonoid bean phytoalexin, phaseollin in planta were carried out for tissues expressing compatible and incompatible interactions to enable a link to be made between reaction phenotypes and restriction of bacterial growth and phytoalexin accumulations. Development of the HR was clearly associated with the restricted multiplication of bacteria during incompatible interactions. A time-course accumulation analysis on pods treated with different races of bacterial agent showed that a strong correlation was observed between the timing and extent of cell death and accumulation of phaseollin, being rapid and extensive in incompatible interactions compared to compatible interaction. 相似文献
4.
Md Romij Uddin Leonard John Wade Jong Yeong Pyon Md Abdul Mazid 《Journal of Crop Science and Biotechnology》2009,12(1):17-23
An experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh in Old
Brahmaputra Alluvial Flood Plain (AEZ-9) during December 2005 to May 2006 to examine the root growth of different rice cultivars
under various establishment methods. This experiment comprised two sets of treatment (i) three methods of planting viz., dry
direct seeding, wet direct seeding and transplanting, and (ii) six rice cultivars, two inbreds viz., BRRI Dhan 28 and BRRI
Dhan 29, two hybrids, viz., Aalok 6201 and Sonarbangla 1 and two local improved cultivar viz., Habigonj IV and Habigonj VIII.
Cultivars had more remarkable effect on different root parameters i.e. number of roots, root length, root length density,
root biomass, root weight ratio and root shoot ratio of hybrid, inbred and local improved rice cultivars than method of planting.
BRRI Dhan 28 performed the best for most of the parameters. At harvest, BRRI Dhan 29 showed the best rooting behavior among
the cultivars. For both stages hybrid rice cultivars showed intermediate and local improved cultivars performed lower in rooting
behavior. Direct seeding method performed better than transplanting method for most of the root parameters but wet direct
seeding and dry direct seeding methods were identical. Interaction effect between method of planting and cultivar in most
of the root parameters were insignificant. But, BRRI Dhan 28 and BRRI Dhan 29 under wet direct seeding method and Sonarbanngla
1 under transplanting method showed the best rooting performance among the other combinations. 相似文献
5.
Three studies were initially conducted using five mint cultivars with known disease reactions to verticillium wilt to determine
if inoculation method, root-dip as compared to root-injection, had an affect on the plant growth and disease reaction. The
planting media did not affect the development of wilt symptoms in susceptible varieties, however, the soil/peat based medium
resulted in higher shoot fresh weight at harvest than the perlite/vermiculite medium. Black Mitcham had the highest susceptible
disease rating and greatest reduction in fresh shoot weight from inoculation with Verticillium dahliae at two inoculum concentrations,
104 or 106 microconidia/ml. Native spearmint was resistant and Mentha crispa was moderately resistant, whereas, Murray Mitcham
peppermint and Scotch spearmint were moderately susceptible to verticillium wilt with a corresponding lower fresh shoot weight.
Scotch spearmint was less susceptible at the low inoculum concentration than at a higher level of microconidia, indicating
a low level of disease resistance. Overall, the two inoculation methods resulted in similar cultivar responses to verticillium
wilt, although the root-injection method was more applicable for large plant populations. Thus, the root-injection method
of inoculation was utilized to screen 743 Black Mitcham derived somaclones for wilt resistance, of which nine somaclones were
found resistant in repeated inoculation tests.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Summary Four cultivars of Populus spp., compatible to varying degrees with four races of M. larici-populina
Kleb., were raised in a controlled environment on a high (28°/20°C, day/night) and low (20°/10°C) temperature regime. Leaf discs cut from the plants were inoculated separately with four individual races of M. laricipopulina and subsequently incubated at either low (20°C) or high (25°C) temperature for 14 days when disease development on the discs was assessed using three parameters (Incubation period to flecking, uredia per leaf disc and uredospores per mm2). The degree of resistance in all cultivar/race combinations was high on cultivars cultured at a high temperature regime compared to those cultured on a low temperature regime. Analysis of variance demonstrated that the major components: pre-inoculation temperature regime, post-inoculation temperature regime, race and cultivar, and most second and third order interactions between these were highly significant (P<0.001) for most disease parameters. The variance of the temperature components and all interactions involving these were usually higher than those for the cultivar and race components and those interactions lacking temperature components.These results emphasize the importance of the temperature regime at which plants are raised and the temperature of incubation, following the inoculation in determining the relative degree of resistance of these cultivars of poplar to races of M. larici-populina. The implications of these results in the epidemiology of leaf rust and the stability of the host-parasite relationship are discussed. 相似文献
7.
采用室内盆栽接种法,测定了全蚀病菌?禾顶囊壳小麦变种对小麦初生根与次生根的侵染性。结果表明,小麦初生根易感全蚀病菌,是禾顶囊壳小麦变种的主要侵染部位,而次生根相对抗病,其发病轻重与次生根的生理年龄和小麦品种的抗病性有关。小麦8793-8较76120抗禾顶囊壳小麦变种的侵染。 相似文献
8.
Variation in the responses of selected genotypes of spring rape to infection by a wide range of isolates of Leptosphaeria maculans was analyzed in this study.Differences in severity of disease damage to seedlings between host and pathogen genotypes were highly significant. Interactions between host and pathogen were also highly significant. The generally resistant cultivar Wesreo was susceptible to a number of isolates whereas the normally susceptible cultivars Zollern-gold and Ceska were resistant to some isolates. Overall, however, Wesreo was resistant to a far greater number of isolates than were the susceptible genotypes.Significant differences in severity of disease damage were also observed between groups of isolates from different sites. All host genotypes were resistant to a substantially greater proportion of isolates from certain sites than from others. Interactions were again detected in that the ranking of sites on the basis of the proportion of isolates causing severe damage varied between host genotypes.The significance of host-pathogen interactions in the B. napus-L. maculans relationship is discussed with special reference to current views on the nature of horizontal resistance. 相似文献
9.
GUO Qing-Yun KUAI Jie WANG Bo LIU Fang ZHANG Chun-Yu LI Gen-Ze ZHANG Yun-Yun FU Ting-Dong ZHOU Guang-Sheng 《作物学报》2020,46(9):1408-1415
近年来,根肿病的迅速蔓延已对我国油菜生产造成严重威胁。课题组前期多年多点大田试验发现,感病、抗病品种混播可显著降低感病油菜品种根肿病发病率。为进一步探究感病、抗病品种播种间距对根肿病的防控效果,本试验采用穴盘栽培,设置感、抗根肿病油菜近等基因系不同播种间距(0、2、4、6 cm),出苗后7 d接种根肿菌,接种42 d后调查幼苗发病率、病情指数,并测定根系主要成分。结果表明:(1)与单播相比,感病、抗病品种同播时,抗病品种苗期发病率无明显变化,而感病品种苗期发病率显著下降,其发病率与感病、抗病品种播种间距密切相关,二者距离为0 cm时的发病率及病情指数均显著(P0.05)低于其他处理;(2)与单播相比,感病、抗病品种同播时,抗病品种和感病品种根中可溶性糖及可溶性蛋白质含量均显著降低,酸不溶木质素含量在感病品种中显著增加,而在抗病品种中呈现先增加后降低的趋势;(3)发病率和病情指数均与根系可溶性糖和可溶性蛋白质含量显著正相关(P0.01),发病率与可溶性糖和可溶性蛋白质含量的相关系数分别为0.797、0.403,病情指数与可溶性糖和可溶性蛋白质含量的相关系数分别为0.822、0.509。综上,油菜感、抗品种混播可以显著降低感病品种的根肿病发病率,且混播间距在0 cm时效果最好。该技术可以作为油菜根肿病防控的技术措施,在根肿病发病区域油菜生产上有着较好的应用前景。 相似文献
10.
The growth behaviour of Dekama (drought tolerant) and Kufri Jyoti (drought susceptible) was studied using potted plants maintained at well watered condition and water deficit condition respectively. Periodic harvestings were done starting from 50 days after planting till maturity. Recordings of plant height, leaf area, dry weights of different plant parts, the proportion of thinner and thicker roots, stomatal conductance and water saturation deficit were obtained. The plant height, leaf area and dry weight of shoot decreased to nearly the same extent in both the cultivars under stress. The stomatal conductance decreased by 61.7 % in Dekama and by 64 % in Kufri Jyoti due to water stress. Water saturation deficit increased by about 80 % in both the cultivars. The ratios of root to shoot and that of thinner to thicker root increased due to stress in both cultivars and this increase was 85 % and 71 % in Dekama and 64 % and 19 % in Kufri Jyoti respectively. The distribution of dry matter to leaf, stem, root were more at the expense of tuber under stress conditions in both cultivars. However, the tolerant cultivar Dekama got adjusted to the stress condition, with more dry matter partitioned to tubers in the last two samplings. The study points out the factors responsible for better drought tolerance of Dekama compared to Kufri Jyoti and the possible physiological traits useful for selecting drought tolerant cultivars. 相似文献
11.
Vas D. Aggarwal Marcial A. Pastor-Corrales Rowland M. Chirwa Robin A. Buruchara 《Euphytica》2004,136(2):201-210
Common beans (Phaseolus vulgaris) are separated into two distinct groups: Andean and Middle American. We identified CAL 143 as the first Andean bean with
resistance to angular leaf spot disease caused by Phaeoisariopsis griseola. Angular leaf spot is the most widespread and economically important bean disease in southern and eastern Africa, and it
is especially severe on the extensively grown Andean beans. Cal 143 was resistant in Malawi, South Africa, Tanzania, and Zambia,
but it was susceptible in Uganda. This was attributed to the presence of races of P. griseola in Uganda not present in the other countries. We identified two additional Andean bean lines, AND 277 and AND 279, with resistance
to angular leaf spot in Malawi. We also characterized the virulence diversity of 15 isolates of P. griseola from southern and eastern Africa into nine different races. Five of six isolates from Malawi and two of seven from Uganda,
obtained from large-seeded Andean beans, were characterized into four different races considered Andean. These were compatible
only or mostly with large-seeded Andean cultivars. The other eight isolates from Uganda, Malawi, and the Democratic Republic
of Congo, obtained from a small- or medium-seeded Middle American beans, were characterized into five different Middle American
races. These were compatible with Middle American and Andean cultivars. CAL 143 was resistant or intermediate under greenhouse
conditions to all but one of the same 15 isolates from southern and eastern Africa, but it was susceptible to an isolate from
Uganda obtained from a medium-seeded Middle American bean.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Influence of High Shoot and Root-Zone Temperatures on Growth of Three Wheat Genotypes during Early Vegetative Stages 总被引：1，自引：0，他引：1
I. S. A. Tahir N. Nakata T. Yamaguchi J. Nakano & A. M. Ali 《Journal of Agronomy and Crop Science》2008,194(2):141-151
High temperatures, whether of shoot or root, are reported to affect shoot and root growth of various plant species. The scanty information available on the differential response of wheat genotypes to high shoot and root‐zone temperatures triggered this investigation to study the response and adaptation of shoot and root growth of three wheat genotypes to high shoot and root‐zone temperatures during early growth stages. Three wheat genotypes; Fang (heat tolerant), Siete Cerros (heat sensitive) and Imam (recent cultivar adapted to a hot irrigated environment) were grown in soil and hydroponically. Three shoot/root‐zone temperatures (23/23, 23/35 and 35/35 °C for the soil experiment and 22/22, 22/38 and 38/38 °C for the hydroponic experiment) were applied at three‐leaf growth stage. High root‐zone temperature alone or combined with high shoot temperature reduced xylem sap flow rate, root dry weight, root length and root/shoot ratio. Unexpectedly, shoot fresh and dry weights and relative growth rate (RGR) were not significantly affected by the high root‐zone temperature except for the susceptible genotype, Siete Cerros, after prolonged exposure in the hydroponic experiment. In contrast, high shoot/root‐zone temperature significantly reduced shoot fresh and dry weights from as early as the first week of the hydroponic experiment. The 38/38 °C treatment also caused significant reduction in RGR and net assimilation rate during the first 2 weeks, but no significant differences were found during the last 2 weeks compared with 22/22 °C. Interesting responses were observed among genotypes in terms of shoot and root dry weights and root/shoot ratio at 38/38 °C treatment. The heat‐sensitive Siete Cerros showed the least reduction in these traits during the first 2 weeks while the heat‐tolerant Fang and Imam responded by greatly reducing their shoot and root weights. The situation was almost reversed with the duration of treatments such that Siete Cerros became the most affected genotype while Fang and Imam were better adapted to high shoot/root‐zone temperature. Specific root weight was the exceptional trait that increased under high temperature treatments. Results indicate that despite the reduction in root length and weight observed under high root‐zone temperature, shoot growth was not much affected suggesting that the use of suitable cultivar coupled with proper management could alleviate most of high root‐zone temperature effects during early growth stages. 相似文献
13.
Three barley cultivars, Shyri, Clipper and Terán, with different levels of partial resistance to barley leaf rust, caused
by Puccinia hordei, were exposed to six levels of the pathogen. These levels were obtained by 5, 4, 3, 2, 1 and 0 fungicide (Propiconazol) applications
respectively and occurred every 15 days starting at 66 days after sowing. No application served as the control treatment.
There were three replicates. The six-row plots were surrounded by a row of a highly susceptible barley cultivar in which the
barley leaf rust arrived naturally in a fairly early plant stage. The disease severity was assessed five times with 15 days
intervals starting at 66 days after sowing. The yields were determined by harvesting the inner four rows of the plots.
An analysis of variance was carried out on the area under the disease progress curve (AUDPC) data and on the yield data. ‘Shyri’
was the least susceptible cultivar, ‘Terán’ the most. The percentage yield losses varied with the six levels of pathogen from
0 to 31.5% (‘Shyri’), from 0 to 46% (‘Clipper’) and from 0 to 63.5% (‘Terán’). The yield losses correlated strongly with the
AUDPC, the linear correlation coefficient being 0.97. The yield losses indicate the importance of the pathogen in Ecuador.
It also means that high levels of partial resistance are needed to prevent significant yield damage. 相似文献
14.
15.
多酚、黄酮及甾醇与番茄抗晚疫病关系 总被引：1，自引：1，他引：0
以对番茄晚疫病抗性较强的番茄品种‘25-1’和易感染番茄晚疫病的品种‘京乐502’为试材,通过人工接种病原的方法,研究多酚、黄酮及甾醇与番茄品种晚疫病抗性之间的关系。结果表明：（1）健康叶多酚类和甾醇类含量在2 个品种间无显著差异;黄酮类含量抗病品种‘25-1’显著高于感病品种‘京乐502’。（2）接种后,多酚类和黄酮类含量在2 个品种中均呈先增后减的趋势。峰值出现时间‘京乐502’晚于‘25-1’。总甾醇含量与番茄晚疫病抗性密切相关。接种晚疫病病原后,2 个品种中总甾醇含量均都呈下降趋势。随着病情的发展,感病品种‘京乐502’的总甾醇含量迅速下降,抗病品种‘25-1’下降较为缓慢。 相似文献
16.
CHEN Er-Ying WANG Run-Feng QIN Ling YANG Yan-Bing LI Fei-Fei ZHANG Hua-Wen WANG Hai-Lian LIU Bin KONG Qing-Hua GUAN Yan-An 《作物学报》2020,46(10):1591-1604
以全国主推的53个谷子品种为材料,在100 mmol L~(-1)混合盐碱(NaCl∶NaHCO_3=4∶1)胁迫下研究了不同谷子品种的耐盐碱性。结果表明,在盐碱胁迫下, 53个谷子品种的发芽势、发芽率、根长、芽长、根鲜重和芽鲜重均受到不同程度的抑制,以对根长的影响最大;相对发芽势与相对发芽率、相对根长与相对芽长及相对根鲜重与相对芽鲜重均呈显著或极显著正相关。通过主成分分析将14个单项性状指标转化为4个主成分,累积贡献率为90.4%;以4个主成分的得分值通过隶属函数分析获得不同品种耐盐碱的综合得分值,并通过聚类分析将53个谷子品种划分为6种耐盐碱类型,其中强耐盐碱品种2个,耐盐碱品种16个,中间型品种17个,盐碱敏感品种6个,不耐盐碱品种9个和极不耐盐碱的品种3个。同时利用回归分析建立了可用于评价谷子耐盐碱性的回归方程D'=0.298+0.037X_2+0.144X_3+0.018X_6+0.209X_7-0.183X_9+0.115X_(11)-0.201X_(12)+0.112X_(13)-0.101X_(14)+0.284X_(15),相对发芽率、根长盐害率、芽长盐害率和根冠比盐害率可以作为谷子耐盐碱性的评价指标。 相似文献
17.
Y. S. Chauhan S. N. Silim J. V. D. K. Kumar Rao C. Johansen 《Journal of Agronomy and Crop Science》1997,178(3):179-183
To develop a preliminary screening procedure for waterlogging resistance, a waterlogging resistant ICP 8379 and a waterlogging susceptible cultivar ICP 7035 were grown i n pots using different growth media and subjected to 6 days of waterlogging. Waterlogging caused a significant reduction in root dry mass of both cultivars which was greater in ICP 7035 than tn ICP 8379, The reduction i n shoot dry mass was comparatively small. The most conspicuous differences between the two cultivars occurred in terms of plant survival. In different soil treatments, ICP S379 showed 0–38 % mortality and ICP 7035 showed 63–100% mortality. The variation in mortality occurred in response to differences in growth medium. Using the growth medium that gave maximum differences, eight additional cultivars were compared along with ICP 7035 and JCP 8379. Significant differences m plant mortality among different cultivars were observed, A number of cultivars showed similar low mortality as ICP 8379, Therefore, there appears to be a potential t o use this method for preliminary screening of a large number of pigeonpea cultivars for waterlogging resistance. 相似文献
18.
Root growth of seedlings of old and new winter wheat cultivars and a spelt wheat at varying levels of nitrogen
Root growth of five old (time period 1882–1920) and five new (time period 1975–1982) winter wheal cultivars and a spelt winter wheat cultivar was investigated in two greenhouse trials. Nitrogen (NH4 NO3 ) was supplied at six (Exp. I) and two (Exp. II) levels (sub- to supraoptimal for shoot growth). The seedlings were grown in sand-filled polyethylene tubes of 4.5 cm diameter and 50 cm length at 20 o C. The plants were harvested 11 (Exp. I) and 12 (Exp. II) days after emergence. At this early stage of development root growth o: old and new cultivars differed only slightly. The old T. aestivum cultivars had more seminal roots. The longest roots of the modern cultivars penetrated into deeper layers of the substrate. For some traits, cultivar: seemed to respond specifically to the varying N-supply. However, there were no significant difference: between old and new cultivars. Neither were old cultivars better adapted to low N-fertilization nor were modern cultivars superior in tolerating toxic concentrations of NH4 NO3 . Increasing N supply changes root growth as follows: decline in root dry matter, increase in shoot/root ratio of dry weight, decrease in number of seminal roots, shortening of axes and more laterals, increase in diameter of the laterals and less significantly of the main roots, increase in density of laterals, decline in root surface area. The number of apices was affected only to a very small degree. 相似文献
Root growth of five old (time period 1882–1920) and five new (time period 1975–1982) winter wheal cultivars and a spelt winter wheat cultivar was investigated in two greenhouse trials. Nitrogen (NH
19.
菜豆锈病菌生理小种研究初报 总被引：1，自引：0，他引：1
1986—1988年秋季,在天津市郊区3个地点采集菜豆锈病菌夏孢子,经在感病品种锦州双季豆上两次单夏孢子分离后,再在4个鉴别品种上分离鉴定,获得锈病菌分离物,最后采用19个国际通用鉴别品种进行锈菌生理小种鉴定.结果表明,天津地区菜豆锈病菌存在两个主要生理小种.这两个小种在鉴别品种Olatne、51051、AXS37、30-7-2上发病等级为3、1、3、2和1、1、3、2.经与Stavely鉴定出来的美国38-57号小种比较,无一相同.因此,暂把3、1、3、2 定为CTJ—1(中国天津一号),把1、1、3、2定为CTJ—2(中国天津二号)小种. 相似文献
20.
L. H. M. Broers 《Euphytica》1989,44(3):247-258
Summary Eighteen spring wheat cultivars were tested in microfields and race nurseries for their partial resistance PR to wheat leaf rust under low and high disease pressure respectively. Large differences existed between the 18 cultivars, Skalavatis 56 being the most susceptible and Ponta Grossa 1 being the most resistant cultivar. Of the three epidemic parameters, disease severity (DS) at the time that the susceptible check was severely diseased and area under the transformed disease severity curve (AUTC) and the logistic growth rate (r), AUTC and DS were highly correlated. Both seemed to be reliable estimators of PR but DS should be preferred for economical reasons. The logistic growth rate seemed to be unsuitable as an estimator of partial resistance.High and low disease pressure gave similar cultivar ranking. PR can be screened and selected equally well in race nurseries with low space, low time and low cost input as in microfields with high space, time and cost input.Cultivar differences in development rate had a large impact on the cultivar differences for amount of disease and can therefore greatly bias the estimation of cultivar resistance. The resistance of early cultivars tended to be underestimated whereas the resistance of late cultivars tended to be overestimated. The effect of differences in developmental rate was most pronounced in the flag leaf. It is advisable to avoid the assessment of disease levels on the flag leaf only and to incorporate in the tests several susceptible and resistant checks that cover the range of development rates in the material to be selected, because otherwise selection for resistance will tend to select also for lateness.Regression of the epidemiological parameters on three components of partial resistance revealed that latency period (LP) is an important factor in determining the resistance observed in the field explaining on average 67% of the observed variation. Adding infection frequency (IF) and urediosorus size (US) to the linear model increased the proportion of the observed variation in the field explained by the components to 80%. This result supports the idea that the components of PR inherit independently, at least, in part. 相似文献