Cucurbit Genetics Cooperative
Other Crop Genetics Cooperatives
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Cucurbit Genetics Cooperative Report 5:14-15 (article 7) 1982

Correlation of Single-plant Yield with Multiple-harvest yield in Pickling Cucumber

Todd C. Wehner

North Carolina State University, Raleigh, NC 27650

There are 2 basic methods for evaluating breeding material for yield: selection based on single plants, and selection based on rows (usually progeny of single plants). Single-plant selection permits the evaluation of more genotypes with a given amount of resources than progeny row selection does, and has been successful for yield improvement of maize (1). The objective of this experiment was to determine the correlation of multiple-harvest yield with single-plant yield for plants grown at 4 densities, and harvested at 2 stages. Several densities were tested because low densities aid in the separation of plants, while higher densities permit more plants to be screened in a given area.

Fifteen cultivars and lines were evaluated in a yield with 2 replications and 5 harvests made between June 15 and 29. Plots were 9 m long and were planted on 1.5 m centers at 64,400 plants/ha. The same 15 cultivars and lines were also planted in small plots at 10,600; 21,400; 64,400; and 128,900 plants/ha. Single plants were harvested at processing (10% oversize fruit) and at mature (seed harvest) stages. Multiple-harvest yield was then correlated with single-plant yield using Pearson produce-moment and Spearman rank correlation procedures. The Pearson and Spearman correlations were similar, so only Pearson correlations are presented.

There was no correlation between multiple-harvest and single-plant yield (Table1). The correlations were best for single plants harvested at processing stage and grown at 64,400 plants/ha (the same conditions under which the multiple-harvest trial was grown and harvested). However, only 2 of the 5 replications for that density and harvest stage had significant correlations, and the average correlation was not significant. Also, single-plant yield was less effective in separating the lines. While there were fairly large differences among lines for multiple-harvest yield, the differences for single-plant fruit number were smaller and the coefficients of variation (CV) were larger (Table 2).

Table 1. Correlation of multiple-harvest yield with single-plant yield at processing stage - 10% oversize fruit, and at the mature fruit stage - seed harvest, for single plants grown at 4 densities.

Density (plants/ha)
Replication
128,900
64,400
21,400
10,600
1
.48++ (.06)
.40+ (.08)
.30 (.55*)
-.11 (-.48++)
2
.04 (-.20)
.56* (-.14)
.01 (.30)
.11 (-09)
3
.37 (.32)
.11 (-.47++)
.22 (.17)
.49** (-.19)
4
-.31
.10 (-.16)
-.11 (.27)
-.03 (.28)
5
-.20 (.04)
.13 (.03)
-.22 (-.07)
-.09 (.07)
Mean
.16 (.02)
.26 (-.13)
.04 (.24)
.07 (-08)

**, *, ++, + Significant correlation at the 1, 5, 10, and 15% levels, respectively.

Table 2. Mean yield of 15 lines of pickling cucumber tested at Clinton, NC in 1981.

Cultivar or line
Seed source
Multiple harvest yield ($/ha)
Fruit number
Processing stage (no./plant)
Mature stage (no./plant)
Castlehy 2012
Castle
3282
2.4
3.1
Greenpak
Harris
3268
3.0
3.3
G 56 D
NCSU
3095
2.4
3.0
Tamor
Asgrow
3008
2.9
3.4
Regal
Harris
2920
2.4
3.2
Multipik
Petoseed
2680
2.8
3.9
PSR 1479
Petoseed
2616
2.4
3.6
Calico
Petoseed
2522
2.3
3.0
Triplemech
Petoseed
2430
2.6
3.0
G 76
NCSU
2282
3.0
3.7
Tempo
Harris
2159
2.7
3.7
Calypso
Harris
2100
2.7
3.1
Explorer
Petoseed
2040
2.7
2.7
Score
Asgrow
2013
2.2
3.2
Sampson
Petoseed
1793
1.9
3.2
LSD (5%)
1099
0.6
1.0
CV (%)
20
37
46

Considering the lack of correlation between multiple-harvest and single-plant yield, it appears that selection for yield should not be based on single plants. The selection unit should probably be at least a single progeny row.

Literature Cited

  1. Mareck, J. H. and C. O. Gardner. 1979. Responses to mass selection in maize and stability of resulting populations. Crop Sci. 19:779-783.
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Department of Horticultural Science Box 7609North Carolina State UniversityRaleigh, NC 27695-7609919-515-5363
Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 23 October, 2009