vulgaris. L. cvs Dark Red Kidney Charlevoix, and near-isogenic Great ... of Phaseolus vulgaris L. beans (LLOYD, 1975; NATTI, 1971; STEADMAN et al., 1972;.
Euphytica
27 (1978) 225523 1
EFFECT OF GENETIC BLENDS OF DRY BEANS (PHASEOLUS VULGARIS) OF DIFFERENT PLANT ARCHITECTURE ON APOTHECIA PRODUCTION OF SCLEROTINIA SCLEROTIORUM AND WHITE MOLD INFECTION1 DERMOT
P. COYNE. University
J. R. STEADMAN
of Nebraska, Lincoln, Nebraska, USA Received
INDEX
and H. F. SCHWARTZ
25 May
1977
WORDS
Disease avoidance mechanism, determinate canopy, plant competition.
and indeterminate
plant habit, genetic resistance, leaf
SUMMARY
The determinate Phaseoh vulgaris L. cvs Dark Red Kidney Charlevoix, and near-isogenic Great Northern Nebraska # 1 were grown in blends with the indeterminate GN Nebraska # 1 in white mold (Sckrotinia sclerotiorum) disease field nurseries. A critical difference between ‘Charlevoix’ and indeterminate ‘GN Nebraska # 1’ is that the latter has a greater leaf area closer to the soil surface, and this is associated with increased numbers of apothecia beneath the canopy and higher disease severity. White mold infection and apothecia number/m’ beneath the canopy of the blends containing ‘Charlevoix’ were significantly reduced in comparison with the severely infected, homogeneous, indeterminate ‘GN Nebraska # 1’. A reduction of white mold infection for the indeterminate ‘GN Nebraska # 1’ was not observed in blends grown under severe or moderate white mold incidence, but did occur under slight incidence in blends containing 65% and 75% ‘Charlevoix’. No significant difference for seed yield occurred between the blends and homogeneous cultivars planted in four experiments under severe, moderate, slight and zero white mold incidence, respectively, except in Experiment 1 under moderate white mold incidence, the blend of 50% indeterminate ‘GN Nebraska # 1’ and 50% ‘Charlevoix’ exceeded the yield of the indeterminate ‘GN Nebraska # 1’. Mean weight ofwhite (‘GN Nebraska # 1’) and red seed (‘Charlevoix’) increased and decreased, respectively, in some blends due to the more vigorous growth of the indeterminate ‘GN Nebraska # 1’.
INTRODUCTION
White mold, caused by Sclerotinia sclerotiorum (LIB.) DE BARY = Whetzelinia sclerotiorum (LIB.) KORF and DUMONT (KORF & DUMONT, 1972)is a major disease of Phaseolus vulgaris L. beans (LLOYD, 1975; NATTI, 1971; STEADMANet al., 1972; ZAUMEYER & THOMAS, 1957). All Great Northern and Pinto cultivars grown are susceptible to S. sclerotiorum. Successful chemical control of the pathogen has been achieved on green beans (NATTI, 1971) but not on the dry bean cultivars grown in Nebraska (STEADMAN et al., 1972). Some sources of germplasm with resistance (ABAWI et al., 1975; ADAM et al., 1973; ANDERSONet al., 1974; COYNE et al., 1977; r Published as Paper No. 5341, Journal Series, Nebraska Agric. Exp.t Station. Research was conducted under Project 2&3.
225
DERMOT
P. COYNE,
J. R. STEADMAN
AND
H. F. SCHWARTZ
et al., 1977a; STEADMAN et al., 1974) or disease avoidance due to plant architecture have been reported (ANDERSENet al., 1960, 1963, 1974; COYNE et al., 1974, 1977; SCHWARTZ et al., 1977a; STEADMAN et al., 1974) but Great Northern or Pinto cultivars with genetic resistance and/or an architectural avoidance mechanism to S. sclerotiorum are still in the future (COYNE et al., 1976). JENSEN (1952) first reported on the value of genetic blends in cereals to reduce damage by rust and research in this area was later reviewed by BROWNING & FREY (1969). With the availability of two determinate bean types that exhibited white mold avoidance (STEADMAN et al., 1973,1974), the use of genetic blends ofthese determinate types and an indeterminate ‘GN Nebraska #l ’ type was attempted to reduce white mold disease in populations. In addition, numbers of apothecia which produce the spores which initiate infection and canopy density were determined. SCHWARTZ
MATERIALS AND METHODS
Four field experiments were conducted during 1974-75 on a Tripp very line sandy loam soil at the University of Nebraska Panhandle Station Farm, Mitchell, Nebraska. A randomized complete block design with the following replications was used; 5 for Experiments 1 and 2, 8 for Experiment 3, and 5 for Experiment 4. Three row plots of each population, 6 m in length, with rows spaced 56 cm apart was used. Seed was planted during the first week of June for all experiments. Weeds were controlled by application of S-ethyl n, n-dipropylthiocarbamate (Eptam) at 3.33 kg/ha and subsequently by mechanical cultivation if required. Furrow irrigation was applied every 7-12 days. Two experiments, designated as Experiment 1 (1974) and 3 (1975), were planted in white mold disease nurseries. The following measures assured favorable conditions for disease development in Experiments 1 and 3 in both years; (1) an abundance of S. sclerotiorum sclerotia were present in the soil (2.80 + 0.36 and 1.81 k 0.27 sclerotia per kg air-dry soil in 1974 and 1975, respectively), (2) two rows of field maize were planted around the experiment to create a windbreak effect to cause humid microclimate, and (3) the soil surface was kept moist during August by weekly furrow irrigations to promote apothecial development and subsequent plant infection by the pathogen. Two experiments, designated Experiments 2 (1974) and 4 (1975) also were planted in fields with a history of a low incidence of white mold and were surrounded on all sides by other bean tields. The various cultivars (homogeneous and homozygous) and genetic blends of these cultivars used in experiments are listed in Table 1. The near-isogenic determinate ‘GN Nebraska #I’ was included in the 1974 experiments but was excluded in 1975. Since the seed differed in size, the blends were prepared by seed count to obtain the required percentage of seed of each cultivar in the blend. Leaf canopy measurements were determined for ‘GN Nebraska # 1’ and ‘Charlevoix’ in the first two replicates of Experiment 3 on August 15, 1975 using exactly the methods and procedures described by SCHWARTZ (1977) and SCHWARTZ et al. (1977a). Apothecia present on the soil surface beneath the plant canopy of each variety or blend were counted in 1.8 m length of the center irrigated row in Experiment 3 on 226
Euphytica 27 (1978)
+ +
-
27.9 a
white
50.4a 47.4 b 28.1 a 48.4 ab 29.8 a 49.1 ab 29.2 a
-
red
seed yield 100 seed weight (kg/ha) (g)
(PI) 100% 1 1 18 a (P3) 100% i419a ( ~ 6~) O % P+ I 5 0 % ~ 3 1137 a (P8) 35% PI + 6 5 % ~ 3 1380 a ( ~ 725% ) PI 7 5 % ~ 3 1242 a
+
1c
25 a
23 ab Ilbc 35.7 ah 9 c 36.7 a 4c
-
35.0 b
white
66 a 17d 35 b 29 bc 26 c
:bserved A plant infection 3 Sept. '75
3.6 ab 2.9 c 3.0 bc 2.8 c
2.5 c
3.9 a
-
33.9 b 36.5 a
-
-
55.7 a 56.2 a
-
-
33.4 b
-
54.2 a
-
white
Experiment 4 - 1975 slight WM
3188 a 2945 a 2722 a 3256 a
2741 a
3295 a
red
Seed yield 100 seed weight (kg/ha) (g)
Experiment 2 - 1974 - Zero WM
41' 34' 29'
-
-
8.6 a 2.3 b 5.9 ab 2.2 b 4.4 b
2926 a 2420 a 2790 a 2751 a 2649 a
46.9 ab 45.0 b 48.2 a 47.0 a
-
32.4 a 32.5 a 33.7 a
-
32.4 a
calculated apothecia seed yield I00 seed weight expected number/m2(kg/ha) (g) % plant 8 Aug.'75 infection red white in blends
1g6 8.46 I 37 6.5'
-
-
ybserved Calculated Canopy /o plant expected density infection1 % plant rating3 3 1 Aug. '74 infection in in blends2
Experiment 3 - 1975 - severe WM
54.7 b 53.5 b
-
-
58.5 a
-
-
red
Seed yield 100 seed weight (kg/ha) (g)
Experiment 1 - 1974 -moderate WM
(PI) 100% G N Nebr. 2249 b5 # 1 (iI4 (Pz 100% G N Nebr. 2984 ab # I (4 (P3) 100% Charlevoix 2508 ab (d) ( ~ 4 ) 5 0 % ~ 1 + 5 0 % P z2760ab ( ~ 5 2) 5 % ~ 1 $. 7 5 % ~2790 ~ ab ( ~ 65) 0 % ~ 5~ 0 % ~2991 ~ a ( P ~2) 5 % ~ 1 7 5 % ~2634 ~ ab
Populations
16.8 a 0.0~ 7.4 b 0.8 bc 1.4 bc
ybserved plant infection 4Sept.75
8.29 5.g9 4.g9
-
-
m
C,
z
m
-
V,
>
5
F
tn
CEI
.rl
0
u m
z
rn
calculated $ expected % plant infection 2 in blends
o
0
0
0 0
-
-
o
0 0
0
0
Observed Calculated % plant expected % infection plant 31 Aug. '74 infection in blends
The percentage (&loo%) plant infection was recorded for each plant in the plot. ZCalculated expected % of plant infection in the blends was based on the proportion of each entry in the blend times the infections level recorded for the pure stand. w Canopy density : 1 = ground readily observed; 2 = observed base of plant; 3 = only observe middle of plant: 4 = only upper leaf layers visible: h, 5 = complete canopy cover of ground. 4 i = indeterminate: d = determinate. Mean separation using Duncan's Multiple Range Test, 5% P level. 6 , 7. 'v9Chi square values indicated no significant difference between expected and observed % plant infection in these separate blend groups in Experiments 1 and 3 (6, 7, 8) at P 0.05 but a significant difference was observed in Experiment 4 (9), xZ = 6.25 < P 0.05.
L
2
I
* V3
h, U
2'
'c,
S,
,h
Table 1. Yield, seed weights and percentage white mold ( WM) plant infection in homogeneous and genetic blend populations in four experiments under different levels of white mold incidence. Canopy density ratings and apothecia number/mz were recorded in experiments 1 and 3 respectively.
DERMOT
P. COYNE,
J. R. STEADMAN
AND
H. F. SCHWARTZ
August 8, 1975 as described by SCHWARTZ et al. (1977a). Apothecia/m’ were then calculated and the results presented in Table 1. Dates of recording data are listed and scales used to measure percentage white mold plant infection and ratings for plant density are explained in a footnote in Table 1. Harvesting of the various plots was done at different dates in September when the pods were dry. Plants in a uniform stand, 1.8 m row length, in the center row of each population were harvested and threshed with a Vogel thresher, cleaned with an aspirator, and weighed. Seed weight of red and white seeds in the genetic blends of indeterminate ‘GN Nebraska #l’ (white) and ‘Charlevoix’ (red) was determined. RESULTS
Percentage white mold infection varied in the different experiments (Table 1). No white mold was observed on any population in Experiment 2. Severe, moderate and slight white mold infection occurred on indeterminate ‘GN Nebraska #l’ in Experiment 3, 1, and 4, respectively. No white mold infection was noted on ‘Charlevoix’ in Experiment 4 but a trace and slight infection occurred in Experiments 1 and 3, respectively. The near-isogenic determinate ‘GN Nebraska #I’ showed slight infection in Experiment 1. The percentage white mold infection for all genetic blends which contained ‘Charlevoix’ and ‘GN Nebraska #l’ was significantly lower than that of the homogeneous indeterminate ‘GN Nebraska #l’. However, ‘Charlevoix’ failed to confer a significant degree of protection to the susceptible ‘GN Nebraska #l’ plants under severe (Experiment 3) and moderate (Experiment 1) levels of white mold infection. This infection was not significantly lower for the blend when the data were adjusted to reflect the proportion of susceptible ‘GN Nebraska #l’ plants present as opposed to a pure stand. However, in Experiment 4 there was a significant white mold reduction for the P7 and Ps blends which contained a higher proportion of ‘Charlevoix’. In this experiment the white mold infection was lower for the indeterminate ‘GN Nebraska #l’ plants in the blend than in the pure stand or homogeneous population. Significant differences in canopy density occurred between indeterminate ‘GN Nebraska #l ’ and determinate ‘Charlevoix’ and accounted for significant differences in apothecia recorded for Experiment 3 (Table 1). The more dense indeterminate ‘GN Nebraska #l’ allowed nearly four times as many apothecia/m2 to develop on the soil surface as did the upright determinate ‘Charlevoix’. A significant reduction in apothecia was observed beneath the canopy of blends P7 and Ps when compared to ‘GN Nebraska #l’ grown under severe white mold incidence levels (Experiment 3). No significant difference in apothecial numbers was observed between blends P,, Ps and ‘Charlevoix’ (Ps). The indeterminate ‘GN Nebraska #l’ had a greater leaf area (986 cm2 per plant) closer to the soil surface (height interval O-20 cm) than did the determinate ‘Charlevoix’ (337 cm2 per plant), thus creating conditions more favorable at the soil surface for apothecial production (Table 1). There was no difference in total leaf area between ‘GN Nebraska #I’ (1424 cm2 per plant) and ‘Charlevoix’ (1566 cm2 per plant), but the canopy profile distribution was different as mentioned above. 228
Euphytica
27 (1978)
BLENDS
OF
BEANS
AND
DISEASE
INCIDENCE
High yields were obtained in Experiment 1, 2 and 4 grown under moderate, zero and slight levels of white mold incidence (Table 1). A large yield reduction occurred only under severe white mold infection in 1975 (Experiment 3). The yield of ‘Charlevoix’ was also considerably reduced in this experiment even though it was not severely infected by white mold. Mean weight of white seed increased in the genetic blend P7 grown in Experiments 1 and 2 but no significant difference occurred in Experiments 3 and 4 (Table 1). A decrease in mean weight for red seed occurred in genetic blend P6 grown in Experiments 1, 3 and 4 but no differences were noted in Experiment 2. DISCUSSION
These genetic blends were not successful in protecting the indeterminate susceptible ‘GN Nebraska #l’ against high white mold infection under a moderate or severe level of white mold incidence. Genetic blends which contained ‘Charlevoix’ (P7 and P,) in Experiment 3, 1975 significantly reduced the apothecial number/m’ beneath the canopies below those observed in a homogeneous stand of ‘GN Nebraska #l’. However, this inoculum reduction was not enough to cause a reduction in white mold infection level. The reduction in apothecial numbers apparently was not sufficient to reduce the epidemic potential within the canopy. No significant differences occurred between the numbers of apothecia/m2 observed beneath genetic blends P6, P7 and Ps and the homogeneous stand of ‘Charlevoix’ (P3) in Experiment 3. However, the percentage white mold infection of ‘Charlevoix’ was significantly lower than those of its blends with ‘GN Nebraska #I’. The lower number of apothecia produced under a pure stand of ‘Charlevoix’ canopy is in agreement with that reported by SCHWARTZ et al. (1977a). However, the effect of genetic blends of different plant types on apothecial production has not been reported. If a level of protection occurred on the highly susceptible ‘GN Nebraska #l’ plants, and the infection level of the determinate plants remained about the same as in pure stand, the observed level of white mold infection in the overall blends would be lower than the level expected based on proportion of each entry in the blend with the same infection level as in the homogeneous population. Under a low incidence of white mold infection in Experiment 4 the genetic blends P7 and Ps did confer some protection from white mold on ‘GN Nebraska #l’. However, this small reduction of white mold did not have a significant effect on yield, and thus, there would be no economic advantage in the use of these blends. The near-isogenic determinate ‘GN Nebraska #I’ had lower white mold infection than the indeterminate ‘GN Nebraska #l’ confirming our earlier finding (STEADMAN et al., 1973). However, it has been observed that both lines are susceptible under conditions highly favorable for white mold development (COYNE et al., 1977; SCHWARTZ et al., 1977a), indicating that plant growth habit conferred architectural avoidance to white mold disease. ‘Dark Red Kidney Charlevoix’ was later found to have a low level of infection in a severe field test (STEADMAN et al., 1974). This was first attributed to an avoidance mechanism due to plant architecture, but in 1975 it was determined that a level of genetic resistance was also involved (SCHWARTZ et al., 1977a). Although ‘Charlevoix’ had only slight white mold infection in Experiment 3, there Euphytica 27 (1978)
229
DERMOT P. COYNE. J. R. STEADMAN AND H. F. SCHWARTZ
was no difference in yield between it and all the other entries which had significantly greater white mold infection. The reduction in yield of ‘Charlevoix’ may be due to a response to excessive irrigation or some other environmental factor, but does not appear to be directly related to disease. High seed yields were observed in entries grown under slight or moderate white mold infections which confirms the findings of STEADMAN & KERR (1975) that yield reductions occur only under high levels of white mold infection (above 35540%). Our results show that the determinate ‘Charlevoix’ and determinate ‘GN Nebraska #l’ can yield as high as the indeterminate ‘GN Nebraska #l’. Previous reports in the literature indicate that determinate ‘Dark Red Kidney’ and ‘Pinto’ beans produce lower yields than indeterminate GN and Pinto cultivars (COYNE et al., 1965, 1973 ; LE BARON, 1970; WILSON, 1962). In Experiment 1 the yield from genetic blend Pg was significantly greater than that of ‘GN Nebraska # 1’ planted in pure stand. This yield response did not likely occur from a reduction in percentage white mold infection in the blend, but instead may be a favorable physiological interaction between blend components in that environment. This genetic blend did not produce a higher yield than ‘GN Nebraska #l’ grown in other experiments. Mean weight of white seed (GN Nebraska #l) and red seed (Dark Red Kidney) increased and decreased, respectively, in some genetic blends in some experiments. These differences could be ascribed to competitive effects between various plant types, and it was expected that the indeterminate would be more competitive than the determinate plant type because of a more vigorous growth habit. A breeding program to combine genetic resistance and architectural disease avoidance to white mold (COYNE et al., 1976) along with microclimate modification due to cultural practices (BLAD & STEADMAN, 1975) offers a much better prospect how genetic blends of achieving a practical and economic level of control of white mold disease in indeterminate dry bean cultivars. ACKNOWLEDGMENTS
The authors appreciate assistance received from former assistants Pam Johnson, Stephen Magnuson, Betty Hoff and numerous staff members of the Panhandle Station, University of Nebraska, Scottsbluff, Nebraska. REFERENCES ABAWI, G. S., R. PROVVIDENTI &J. E. HUNTER, 1975. Evaluating bean germplasm for resistance to Whetzelinia sclerotiorum. Proc. Am. Phytopath. Sot. 2: 50 (Abstr. No. 122). ADAMS, P. B., C. J. TATE, R. D. LUMSDEN &J. P. MEINERS, 1973. Resistance of Phaseolus species to Sclerotinia sclerotiorum. A. Rep. Bean Improv. Coop. 16: 8-9. ANDERSEN, A. L., E. E. DOWN & G. WHITFORD, 1960. The Sanilac pea bean - its history, development and characteristics. Mich. State Univ. Agric. Exp. Stn Quart. Bull. 42: 214-236. ANDERSEN, A. L., M. W. ADAMS & G. WHITFORD, 1963. The Seaway pea bean, development and characteristics. Mich. State. Univ. Agric. Exp. Stn Quart. Bull. 45: 548-559. ANDERSON, F. N., J. R. STEADMAN, D. P. COYNE & H. F. SCHWARTZ, 1974. Tolerance to white mold in Phaseolus vulgark dry edible bean types. PI. Dis. Reptr 58: 782-784. BLAD, B. & J. R. STEADMAN, 1975. Relationship of microclimate and white mold disease in dry bean Euphytica
27 (1978)
BLENDS OF BEANS AND DISEASE INCIDENCE crops as influenced by irrigation and canopy structure. Agron. Abstr. p. 10. BROWNING, J. A. & K. J. FREY, 1969. Multiline cultivars as a means of disease control. Am. Rev. Phytopath. 7: 355-382. COYNE, D. P., J. R. STEADMAN & F. N. ANDERSON, 1974. Effect of modified plant architecture of Great Northern dry bean varieties (Phaseolus vulgar@ on white mold severity, and components of yield. Pl. Dis. Reptr 58: 379-382. COYNE, D. P., J. R. STEADMAN & STEPHEN MAGNUSON, 1976. Breeding for white mold disease resistance and avoidance due to ideotype in beans. A. Rep. Bean Improv. Coop. 19: 21-23. COYNE, D. P., J. R. STEADMAN & H. F. SCHWARTZ, 1977. Reaction of Phase&s dry bean germplasm to Sclerotinia sclerotiorum. Pl. Dis. Reptr 61 : 226-230. COYNE, D. P., F. N. ANDERSON, A. F. HAGEN, 0. W. HOWE & M. L. SCHUSTER 1965. Field bean production in Nebraska. Univ. Nebr. Agric. Exp. Stn Bull. 486: I-19. COYNE, D. P., F. N. ANDERSON, C. L. ASHBURN, C. R. FENSTER,A. F. HAGEN, 0. W. HOWE, D. W. LANCASTER, M. L. SCHUSTER& J. R. STEADMAN, 1973. Growing dry edible beans in Nebraska. Univ. of Nebr. Agric. Exp. Stn Bull. 527: l-39. KORF, R. P. & K. P. DUMONT, 1972. Whetzelinia. a new generic name for Sclerotinia sclerotiorum and S. tuberosa. Mycologia 64: 248-250. JENSEN.N. F.. 1952. lntra-varietal diversification in oat breeding. J. Am. Sot. Agron. 44: 30-34. LE BARON, M., 1970. Report of the cooperative dry bean nurseries. Univ. of Idaho Agric. Exp. Station p. l-7. LLOYD, E. H., 1975. White mold of Pinto beans: Effects on yield and fungicidal control. North Dakota Farm Res. 32: 9-14. NATTI, J. J., 1971. Epidemiology and control of bean white mold. Phytopathology 61: 669474. SCHWARTZ, H. F., 1977. Epidemiology of white mold disease (Sclerotiniu sckrotiorum) = (Whetzelinia sclerotiorum) of dry edible beans (Phaseolus vulgaris) with emphasis on resistance and host architectural disease avoidance mechanisms. Ph. D. Thesis, University of Nebraska, Lincoln. Nebraska. 145 Pg. SCHWARTZ. H. F., J. R. STEADMAN & D. P. COYNE, 1977a. Resistance of Charlevoix and Valentine to infection by Sclerotinia sclerotiorum. A. Rep. Bean Improv. Coop. 20: 71-72. SCHWARTZ, H. F., J. R. STEADMAN & D. P. COYNE, 1977b. Influence of Phaseolus vulgaris blossoming characteristics and canopy structure upon reaction to Schrotinia sclerotiorum. Phytopath. 67 (In press). STEADMAN, J. R. & E. D. KERR, 1975. Relationship between white mold disease severity and seed yield of dry edible beans. A. Rep. Bean Improv. Coop. 18 : 78-79. STEADMAN, J. R.. E. D. KERR &J. L. WEIHING, 1972. White mold disease of field beans in Nebraska. Univ. of Nebr. Agric. Exp. Stn Bull. 518: l-10. STEADMAN, J. R., D. P. COYNE & G. E. COOK, 1973. Reduction of severity of white mold disease on Great Northern beans by wider row spacing and determinate plant growth habit. Pl. Dis. Reptr 57: 1070-1071. STEADMAN, J. R., D. P. COYNE & H. F. SCHWARTZ, 1974. Field reaction of beans to severe white mold infection. A. Rep. Bean Improv. Coop. 17: 84-85. WILSON, V. E., 1962. Report of the cooperative dry bean nurseries. USDA and Univ. of Idaho Agric. Exp. Stn l-13. ZAUMEYER, W. J. & H. R. THOMAS, 1957. A monographic study of bean diseases and methods for their control. USDA tech. Bull. 868.
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