Screening of Melons for Sweetpotato Whitefly Resistance: 1992

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Cucurbit Genetics Cooperative Report 16:49-52 (article 18) 1993

James D. McCreight
U.S. Department of Agriculture, Agricultural Reesearch Service, U.S. Agricultural Research Station, 1636 East Alisal Street Salinas, CA 93905, USA

Sweetpotato whitefly, Bemisa tabaci Genn. (SPWF) B strain virtually destroyed the Fall 1991 melon crop in the lower desert valleys of Arizona and California (4). SPWF-B does not appear to be an important vector of lettuce infectious yellows virus (LIYV, 1). In 1991, 17 of 150 PIs from India appeared to have some level of resistance to SPWF-B (3). In 1992, these 17 PIs were retested for SPWF-B resistance along with 108 previously untested PIs from India plus 27 standard varieties, breeding lines, and F1, F2 and backcross families from crosses among LIYV and SPWF-B resistant and susceptible parents.

A field test to evaluate SPWF-B resistance was planted on August 5 at the USDA, Irrigated Desert Research Station, Brawley, California. Plots were planted on 80 inch centers and consisted of five two-plant hills spaced 30 inches apart; there were two replkications. Plots were treated once with Thiodan shortly after emergence for flea beetle control. The test wasevaluated on a plot basis for four eeks (September 2 and 3) and eight weeks (September 30) later for number of live plants, plant size, plant condition, yellowing, leaf necrosis (burn) and flowering.

The SPWF-B population at Brawley during the test period was high. Four weeks after planting (September 2-3), mean number of plants per plot, and plant size and condition varied among the entries (Table 1). Becaue of little foliar yellowing was observed, yellowing data are not presented. A few entries had begun to flower, and as expected none of the entries was large enough to completely cover the bed. Plant condition was in general very good at this time. After an additional four weeks (8 weeks after planting) the plots had deteriorated. Many plants died; the proportion of plants surviving ranged fromzero for 41 entries to 85% for one entry (F1 Freeman Cucumber x Snakemelon); nine other entries had survival rates > 50% (PI 271329 , PI370021 , PI 381775 , PI 277281 , BC Snakemelon (Freeman Cucumber x Snakemelon), BC Freeman Cucumber (Freeman Cucumber x Snakemelon) , F2 Freeman Cucumber x Snakemelon , PI 145594 , PI 210542). Despite the higher survival rates, these lines were comparable to lines with lower (,50%) survival rates for plant size and condition. It is, however, significant to note that Snakemelon had a 42.1% survival rate and that F1, F2 and BC families from crosses of Snakemelon with Freeman Cucumber combrised four of the 10 entries with survival rate < 50%. Snakemelon, and BC Snakemelon (Freeman Cucumber x Snakemelon) were among the best five entries for plant condition after eight weeks. Five entries had a mean plant condition. 3.0 (PI 212895 , Snakemelon , BC Snakemelon (Freeman Cucumber x Snakemelon) , F2 (90625 x Top Mark) , PI 370021). Snakemelon was previously identified as a potential source of LIYV resistance and has very large vines in the presence of high levels of LIYV (2).

In 1991, a single plant of PI 164825 appeared to be resistant to SPWF-B feeding. Self-pollinated seed from that individual was not obtained, but crosses were made with WMR 29 and I5. PI 164825 was retested in this test but none of the plants were as outstanding s the individual observed in 1991. The two F1 families made with PI 164825 were not remarkable (Table 1). PI 145594 was the only PI identified in 1991 as a potential source of SPWF-B resistance that performed well in this test (Table 1). Five PIs tested for the first time in 1992 were among the best entries for survival, and plant size andconditin after eight weeks. These will be retested.

None of the entries in this test was superior for survival, and plant size and condition. Snakemelon from the Middle East and families from crosses of Snakemelon were among the best entries in 1992 for plant survival, size and condition after eight weeks exposure in the field to SPWF-B. Five previously untested wild melon intro9ductions from India PI 210542, PI 271329, 277281, 370021, PI 38775) were identified in 1992 as having some potential as sources for SPWF-B resistance. The better lines for these characteristics will be examined in subsequent field tests exposed to natural populations of SPWF-B. They should also be compared with Top Mark and other varieties in controlled greenhouse tests for response to SPWF-B feeding and reproduction.

Table 1. Mean number per plotz, plant sizey and conditionx on September 2-3, 1992 and changes in these parameters on September 30 in response to sweetpotato whitefly feeding.

September 2-3

September 30

Group and Entry
Live
Size
Cond
% Surv
∆ Size
∆ Cond.
 Varieties and Parental Lines

90625

 9 2 9 16.7 1 -8

AR 5

 8 1.5 8 37.5 -0.5 -7

Freeman Cucumber

 9 2 8.5 16.7 -1 -7.5

PMR Honeydew

 8 1.5 7 06.2 -0.5 -6

Snakemelon

 9.5 2.5 6.5 42.1 2 -3

Top Mark

 7.5 1.5 7 40 -0.5 -6

WMR 29

 9.5 1 6 21.0 0 -4
Snakemelon x Freeman cucumber

F1 FC x Snake

 10 2 7.5 85 1 -4.5

F2 FC x Snake

 20 2.5 6 75 1.5 -4.5

BC FC (FC x Snake)

 10 2 7 70 0.5 -5

BC Snake (FC x Snake)

 8.5 3 6.5 58.8 2 -3
90625 x AR 5

F1 90625 x AR 5

 10.5 2.5 7.5 0 — —

F2 90625 x AR 5

 9 1.8 6.8 27.8 -0.5 -4.2

BC (90625 x AR 5) x AR

 8 2 7 31.2 -0.5 -6
90625 x Top Mark

F1 90625 x Top Mark

 9.8 2 7.5 12.8 -0.3 -6.5

F1 Top Mark x 90625

 9.5 2.2 7.8 32.2 0 -6.2

F2 90625 x Top Mark

 9.5 1.8 7 5.3 3.2 -3

F2 Top Mark x 90625

 9.5 2.5 7.5 31.6 2.5 -5

BC Top Mark x 28377

 9.5 2 6.5 13.2 -1 -5.5

BC 28380 x Top Mark

 10.2 2 7 9.8 -1 -6

BC 28380 x 90625

 9.2 2.2 7.8 13.5 0.8 -6.4

BC Top Mark x 28380

 10 2 8 17.5 -1 -5.8
90625 x PMR Honeydew

F1 PMR ND x 90625

 9.5 2.5 8 15.8 0.5 -7

F2 PMR ND x 90625

 7.8 1.8 7.5 25.8 -0.5 -5.5
PI 164825 crosses
F1 PI 164825 x WMR 29 1 2 7.5 0 — -7
F1 PI 164825 x 15 7.5 2.5 6.5 26.7 -0.5 -5.5
Plant Introductions tested in 1991

123682

 7 1 5.5 7.1 0 -4.5

124092

 8.5 2 5.5 0 — —

124103

 10 1.5 5.5 5 -0.5 -4.5

124106

 6.5 1.5 5 15.4 1.5 -3

124109

 9.5 2.5 6.5 0 — —

124431

 7 2 5 0 — —

124440

 10 2 5 0 — —

124447

 6.5 2 5 0 — —

124550

 9.5 2.5 7 10.5 1.5 -6

145594

 9 2 9 77.8 1 -6.5

164749

 8 2 7.5 12.5 0 -6.5

164825

 8.5 2 5.5 11.8 1 -4.5

165515

 9 2 5.5 5.6 3 -4.5

165525

 7.5 1 6.5 13.3 0 -5.5

179669

 9.5 2 7 26.3 1 -6

179671

 6 2 6 0 — —

179890

 10 2 6.5 0 — —
Plant Introductions tested in 1992

179901

 9.5 2 6.5 10.5 0 -5.5

179902

 8.5 2 6.5 17.6 1 -5

179903

 10 3 6.5 45 0 -5.5

179904

 8 2 6.5 0 — —

179905

 9.5 2 6.5 10.5 0 -4.5

179906

 8.5 2 6.5 11.8 0 -5.5

179909

 8 3 8 25 0 -6.1

179911

 6 2 6.5 25 0.5 -5.5

179913

 10 2.5 6.5 0 — —

179915

 10 2.5 7.5 35 -1.5 -6

179916

 10 2 5.5 5 -1 -4.5

179916

 10 3 7.5 5.5 1.5 -6

179917

 10 3 7.5 5.5 1.5 -6

179919

 10.5 2 6.5 9.5 1 -5.5

179920

 9.5 2.5 6.5 15.9 0.5 -5.5

179922

 6.5 1 8.5 15.4 0 -6.5

179923

 6 1 9 0 — —

180280

 6 1 6.5 8.3 0 -3.5

180281

 7.5 1.5 7 13.3 -0.5 -5

180283

 5 1 7.5 30 0 -5.5

181051

 9.5 2 6 10.5 2 -3

182937

 6.5 2 8.5 0 — —

182938

 9.5 2 6.5 0 — —

182943

 9 1.5 5 5.6 -0.5 -4

182949

 8.5 2 6 17.6 0 5

182952

 10 2 6 5 -1 -5

182959

 9 2 6.5 22.2 -0.5 -5

182964

 5 1.5 9 20 0.5 -8

183025

 7.5 2 5.5 6.7 -1 -4.5

183029

 9.5 2 6 0 — —

183031

 10 2 5.5 0 — —

183032

 8 1.5 5 0 — —

183036

 10 1.5 5 0 —

183040

 10 1 6 11.8 0 -5

183045

 8.5 2 6 0 — —

183048

 7 1 4 8.3 0 -3

183049

 6 2.5 6 5.9 0.5 -5

183051

 8.5 2 6.5 15.4 -1 -5.5

183052

 6.5 2 8 9.1 1 -6

183054

 9 2 7 27.8 2 -4.5

183055

 9.5 2.5 7.5 0 — —

183128

 10 2.5 6 10 -1.5 -5

183303

 10 3.5 7 30 -0.5 -6

183305

 9.5 2 6 10.5 2 -3

183307

 3.5 1 8.5 0 — —

183311

 9.5 2.5 6 5.3 -1.5 -4

183397

 10 2.5 7 15 0.5

183444

 9.5 1.5 6.5 26.3 1

210077

 10.5 1.5 7 14.3 0.5 -6

210541

 8 12 8.5 81 1 -5

210542

 8.5 2.5 7 2 0.5 -6

212803

 8.5 2 7 25 1.5 -6

212895

 8.5 2.5 6 29.4 1 -3.5

213247

 8.5 2 6 5.9 1 -5

214048

 8.5 2.5 7 0 — —

214154

 9.5 2 6.5 0 — —

214318

 9.5 2 7 0 — —

216030

 9 2 6 22.2 -0.5 -4.5

217599

 8.5 2 6.5 11.8 0 -5

271329

 10 2 8 50 1.5 -7

271335

 10 2 6.5 10 0 -5.5

275633

 8.5 2 6.5 17.6 -1 -5

277281

 9.5 2.5 8 57.9 2 -6.5

277282

 8 2 6.5 6.2 -1 -5.5

277283

 9 2 6 0 — —

277284

 9 2 5.5 0 — —

279367

 9 2 6 0 — —

288330

 9 2 6.5 16.7 0 -5

288333

 10 2 7 20 1 -5.5

302445

 10 3 6.5 25 1 -5

302446

 9 1.5 7 0 — —

323316

 8.5 2.5 7 5.9 -1.5 -5

358942

 8.5 2 7 17.6 0 -5.5

370020

 9 2 6 0 — —

370021

 10 3 7.5 50 0.5 -3.5

381758

 9.5 2.5 6.5 0 — —

381760

 7.5 2 7 26.7 -1 -6

381761

 9.5 1.5 6 10.6 -0.5 -4

381762

 8.5 1.5 6 11.8 0 -5

381765

 7 1.5 6.5 21.4 0 -5.5

381766

 8.5 2 7 0 — —

381770

 7.5 2 6.5 0 — —

381771

 7.5 1.5 5.5 6.7 -0.5 -4.5

381772

 9.5 1.5 6 10.5 -0.5 -4

381773

 10 1 5.5 10 0 -4.5

381774

 9.5 2 7 5.3 -1 -6

381775

 8.5 2 9 52.9 1.5 -7

381773

 10.5 2 7 19.0 0.5 -6

381781

 10 2.5 7.5 5 -0.5 -6.5

381782

 10 1.5 6.5 10 -0.5 -3.5

381783

 9 2 7.5 38.9 0.5 -6.5

381784

 8.5 2 6 5.9 0 -4

381786

 10 1.5 6.5 15 -0.5 -5

381787

 10 2 7.5 20 -0.5 -6.5

381788

 9.5 2 7 21.0 -1 -6

381790

 7.5 2 8 6.7 — -7

381792

 10 2 7 0 — —

381794

 10 1.5 6 10 -0.5 -5

381797

 7 2 8 42.8 0.5 -6.5

381800

 9.5 2 8 0 — —

381802

 10 2 6 30 1 -4.5

381803

 8 1.5 5.5 6.2 -0.5 -2.5

401731

 8 1.5 7 12.5 -0.5 -6

431581

 10 1.5 6.5 0 — —

504523

 5.5 1.5 6.5 0 — —

504524

 8.5 1.5 4.5 0 — —

504525

 10 2.5 6.5 5 1.5 -5.5

504526

 7.5 2.5 6.5 0 — —

504527

 9.5 2 5.5 0 — —

zNumber of live plants is the mean; Surv is the Percentage plants remaining on September 30.
y Size was rated on 1 (very small, only a few true leaves) to 9 (completely covering the bed) scale.
x Condition was rated on a 1 (dead) to 9 (vigorous, flowers) scale.

Literature Cited

  1. Cohen, S. J.E. Duffus, and H.Y. Liu. 1991. A new Bemisia tabaci biotype in the Southwestern United States and its role in silverleaf of squash and transmissionof lettuce infectious yellows virus. Phytopathlogy 82:86-90.
  2. McCreight, J.D. 1991. Potential sources of resistance to lettuce infectious yellows in melon. Cucurbit Genet. Coop. Rpt. 14:51-52.
  3. McCreight, J.D. 1992. Preliminary screening of melons for sweetpotato whitefly resistance. Cucurbit Genet. Coop. Rpot. 15:59-61.
  4. Perring, T.M., A. Cooper, D.J. Kazmer, C. Shields, and J. Shields. 1991. New strain of sweetpotato whitefly invades California vegetables. California Agriculture 45 (6):10-12.