Breeding for cabbage root fly (<i>Delia radicum</i>) resistance in cauliflower

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Reference

Breeding for cabbage root fly ( Delia radicum ) resistance in cauliflower

FREULER, Jost, GAGNEBIN, François, STRASSER, Reto

Abstract

Selection of parental lines was continued according to biannual cycles bringing the plant material in the odd years cycle up to F₄ in 1991 and in the even years cycle to the same stage in 1992. The greatest difference between the lines with the lowest (1.3) and the highest mean number of eggs per plant (28.7) was found in 1990 (or 22 fold). Steady progress of level of resistance from one generation to the other is difficult to achieve. Seggregation of high and low egg numbers within descendants of the same parent was first observed in F₄ in 1991.

Some 1991 lines showing levels of resistance were grown in an area of higher fly population.

The root damage index confirms the results of the eggcounts.

FREULER, Jost, GAGNEBIN, François, STRASSER, Reto. Breeding for cabbage root fly (Delia radicum) resistance in cauliflower. Bulletin OILB/SROP / Organisation internationale de lutte biologique et intégrée contre les animaux et les plantes nuisibles, Section régionale ouest paléarctique, 1993, vol. 16, no. 5, p. 6-12

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http://archive-ouverte.unige.ch/unige:121019

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1 / 1

BREEDING FOR CABBAGE ROOT FLY

(Delia radicum)

RESISTANCE IN CAULIFLOWER ·

J. Freuler¹, F. Gagnebin² & R. Strasser²

1 Station federale de recherches agronomiques de ·changins, CH-1260 Nyon (Switzerland)

2 Universite de Gen~ve, Laboratoire bioenergetique, CH-1254 Lullier (Switzerland)

Summary

Selection of parental lines was continued according to biannual cycles bringing the plant material in the odd years cycle up to F ₄ in 1991 and in the even years cycle to the same stage in 1992. The greatest difference between the lines with the lowest ( 1.3) and the highest mean number of eggs per plant (28. 7) was found in 1990 (or 22 fold).

Steady progress of level of resistance from one generation to the other is difficult to achieve.

Seggregation of high and low egg numbers within descendants of the same parent was first observed in F₄ in 1991.

Some 1991 lines showing levels of resistance were grown in an area of. higher fly population. The root damage index confirms the results of the eggcounts.

Introduction

IPM programs include partial resistance of host plants to insect pests because it allows reducing chemical treatments by spraying less frequently or by reducing the dosage which expectedly will have a positive effect on parasites and predators of the target pest.

Material and methods

Since 1979, investigations have been made on, the antixenosis (non-preference) resistance type of cauliflower (Brassica oleracea var. botrytis) to the cabbage root fly (Delia radicum L.). Cauliflower is regionally an important crop and although it is very attractive to cabbage root fly the tolerance threshold of this stem cruciferous for CRF is much higher than with root cruciferous.

The relative level of resistance was determined by counting eggs laid on the stem of the plant. Egg counts on a great number of plants have become feasible with the egg trap. The cultivars were fieldgrown in experimental plots and exposed to a naturally occurring fly population.

' The experimental site was located at Lullier near Geneva. It has proved to be suitable since the fly population is sufficiently high to reveal genetic variations among the plants without compromising their survival.

The experimental layout used was a randomized block design with 5 replicates. Each subplot comprised 20 plants in a double row, and 8 plants were sampled for eggs.

In order to synchronise plant growth and maximum egg laying which takes place during July and August, ttie sowing time chosen was the beginning of Mai followed by

planting out before mid-June. OEPARTEMENT DE BPT~NIOUE

ET DE BIOLOGIE yEGETALE

BIBLIOTHEQUE

Bulletin OILB/SROP Vol. 16 No.5 (1993) pp 6.12 ^{3 place} de l'Universite 'r.H-1211 GENEVE 4

Egg counts take place 4-5 times in 10 days intervals between the beginning of July and the end of August. This ensured that 68%-92% of the laid eggs were trapped, which is supposed to be sufficient to minimize an eventually occuring effect on cauliflower which was described by ELLIS et al. (1979) for radish where a modification of the attractivity of the plant intervenes according to its physiological age.

In order to avoid influence of the plant size on egg laying the development of the plants in the subplots was estimated since 1990 between end of July and beginning of August by calculating the average between the measures of the hight and the diameter of the greatest and the smallest plant per subplot. Subplots with extreme low or high developped plants were discarded for selection and statistical analysis.

The selection scheme consisting of setting up lines from non-attractive individual plants of proven commercial value was dictated by ttie fact that the differences in egg counts, significant between cultivars, are even more strikingly significant between individual plants within a cultivar.

Selection followed the end of egg counts and ended in September considering the quality ot the leaves and the curd as well as the number of eggs.

The growing period of the crop chosen in these trials meant that plants matured when day length and temperature had decreased, creating poor conditions for seed production.

. Therefore, the

in vitro

culture technique was introduced in 1983.

Plants selected in the fall were multiplied during the winter and regenerated plantlets obtained from the same curd flowered after a period of vernalisation the following year for allogamous and autogamous pollination by caging them in the greenhouse. ·

Hence two biannual selection cycles could be started, one occurring in odd years from 1983 onwards ·and the other occurring in even years starting in 1984.

In order to detect undesirable heterogeny effects of

in vitro

culture a verification takes place during the seed production on the plants born from the tissues

in vitro.

Vegetative cha.racters concern leaves, stem and development of inflorescence and reproductive characters development of floral stems, flowers, flowering abundance, faculty of autopollination, fruit and seed. In addition, after several tube transfers selected lines were periodically cropped in the field to observe normal curd productiol'.l-..:-~.. -

Progress in selection was estimated by using standard types mostly lmperator (XIV) since 1981 and sometimes Panda (X) since 1989 for a comparison of egg numbers on progenies selected for resistance (,1) or susceptibility (J').

When egg counts are adjusted in relation to standards, comparisons between parents and its progenies can be made.

Results

Since the last meeting of the working group in 1989 in Marcelin, 3 more selection cycles have been runned: 2 even year cycles in 1990 and 1992 and 1 odd year cycle in 1991.

In 1990, most lines are in the 3rd generation .(tab. 1). General egglaying is rather low. The mean number of eggs per plant varies from 1,3 to 28, 7 (or 22 fold). Most of the eggs are faun on the reference. Nrs 10, 11 and 9 have the reference as parent with quite different selection success, although there is no statistical differences between these lines. We observe no reaction for selection for susceptibility. ·

In 1992, most lines are in the 4th generation (tab. 2). General egglaying is rather high. The mean number of eggs per plant varies much less from 19,8 to 49,4 (or 2,5

fold). The reference is again among the lines with most eggs. No reaction for s~lection.

for susceptibility is observed.

In 1991, most lines are in the 4th generation (tab. 3). General egglaying is rather low. The mean number of eggs per plant vari~s from 2,8 to 28,9 (or 10 fold). This time, the reference is located nearly on top of the list. We observe a good reaction for selection for susceptibility as all lines selected for high egg numbers are at the end of the list. The most interesting case occurs within descendants of the reference where we find for the first time a good seggregation between selected lines for resistance (nr 11) and susceptibility (nr 16). The results of the 4 generations appear in fig. 1.-

Discussion

·Looking through all results some of them are puzzling. With continuing parental selection, the reference, one of the parents, es expected to be located more and more down the ranked list together with lines with relatively high egg numbers. This is the case for the even years selection cycle but not at all for the odd one where the reference is somehow jumping forward and backward in the ranked list. ·

Having some doubts about the stability of the reference, we compared old with new seed of the reference (tab. 2, ·nrs 20 and 21 )and also two susceptible varieties (tab. 2 nrs 22 and 23). The results lead to the conclusion that the reference is stable and considered as quite susceptible. So we lost in some lines going from one generation to the other levels of resistance [e.g. tab. 1, nr 10 (1990)-tab. 2, nr 10 (1992)]. This · could be due to a bad choice of the selected plant or to effects during in vitro culture.

Perhaps also do we have to run the selection for some more generations as the first seggregation occured only in F ₄ or in contrary have we reached a level of resistance, where it is no more worthy going on.

In the meantime, we started to expose the selected material to a higher fly population in a typical cauliflower growing area. This has been done in 1992 in the Valais with some 1991 lines.

The roots were scored using the root damage index (Winfield & Wardlow, 1966;

Thompson et al., 1980) (tab. 4). These figures confirm the results of the eggcounts. · References

, '

ELLIS, P.R., HARDMAN, J.A.,·CRIPS, P. and JOHNSON, A.G. (1979). The influence of plant age on resistance of radish to cabbage root fly egg-laying. Ann. appl. Biol.

93: 125-131.

FREULER, J., FISCHER, S., GAGNEBIN, F. et.BONNET, J.C. (1984). Premiers resultats entomologiques et de selection pour I' obtention de choux-fleurs resistant ii la mouche du chou (Delia radicum). Rev. hart. suisse 57 (3): 67-72.

FREULER, J. and GAGNEBIN, F. (1984). Preliminary entomologist's and plant breeder's results on searching for cauliflower resistant to cabbage root fly, Delia radicum (brassicae) L. /OBC/WPRS Bulletin Vll/4: 49-50.

FREULER, J., GAGNEBIN, F. & STRASSER, R., 1990. Current studies on resistance to cabbage root fly (Delia radicum) in cauliflowers. IOBC/WPRS BULLETIN Xllll6: 4- 12.

GAGNEBIN, F. & FREULER, J. (1988). Progress in the studies of resistance to cabbage root fly (Delia radicum) in cauliflower. IOBC/WPRS Bulletin Xl/3: 67-69.

THOMPSON, A.R., PERCIVALL, A.L. & EDMONDS, G.H. (1980). A comparison of techniques using field plots with fixed doses or log-dose dilutions to evaluate the

performance of single-plant drenches with chlorfenvinphos for the protection of. early summer cauliflowers against Hylemya brassicae. JOBC/BULLETIN 111/1: 137-

144. ' . .

WINFIELD,.A.L. & WARDLOW, L.R. (1966): Cabbage root floy on summer' caulifowers on a silt soil. Experlmentai Horticulture 16: 88-101. · ·

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Table 1:

Nr.

18 5 10 17 1 6 11

7 13 14 12 15 16 4 3 9 19 2 8 21

Egg counts in 1990 on cauliflower varieties and progenies selected for. . resistance (,() or susceptibility ()') to cabbage ro"ot fly during the series of even years.

Variety / line Mean number of Significance

cabbage root fly eggs

- per plant

XVll/64/56 ^,( 1,3

a

X/20, 1/69/38/36 ^,( 1,4 a

XIV/66/14/4 ^,( - 1,5 a

XVll/30/21 ,/. 2,5

-

ab

111/44/34/17 ^,( 4,8 ab

X/20,5/9/21/45 ^,/ 6,0 abc

XIV /66/14/42 ^,( 6,4 abc

X/20,5/73/31/45 ^,/ 7,4 abc-

xv

^{/25/20/68 ,( 7,8 abc}

XVl/27 /22/60 ^,( 7,8 abc

XV/25/5/87 ^,( 8,8 abc

XVl/4 7 /59/63 ? 9,5 abc ..

XVl/93/39/12 ^,( 10, 1 abc ^,

X/20, 1/31/26/38 ^,( 11,0 abc

111/44/54/27 ? 11,5 abc

. XIV/35/38/44 ^,( 12, 1 abc

XX/4 ^,/ 13,9

be

111/44/34/8 ^,( 17,4 cd

XIV /35/38/23 ^,/ 26, 1 de

XIV

-

28,7 e

Table 2:

N'r

17 18 16 19 4 3 2 6 9 1 8 15 12 5 13 14 20 21 10

7 22 23 11

Egg counts In 1992 on cauliflower varieties and progenies select~d for . , resistance ~,/) or susceptibility ()') to cabbage root fly during the series of even years.

PLANT Mean number Significance

of cabbage root fly eggs per plant .

XVll/30/21 /48 ^,/ 19,8 a

-

XX/4/25 ^,/ 22,7 ab

XVll/30/21 /28 ^{,/ :} 25,2 abc

XX/4/29 ^,/ 28,4 a bed

X/20 ^I 1 /31 /26/38/23 ^,/ 31,5 bcde

111/44/54/27 /81 ^.)' 32,7 cdef

111/44/34/17 /97 ^,/ 32,9 cdef

X/20,5/73/31/45/47 ^,/ 33,1 cdef

XIV /35/38/44/80 ^,/ 33,2 cdef

111/44/34/8/66 ,/ • ^33,9 cdef

XIV /35/38/23/63 ^,/ .34,0 cdef

XVl/27 /22/60/63 ^,/ 35,4 def

xv

/25/20/68/21 ^,/ 35,7 def

X/20, 1 /69/38/36/60 ,/ 37,0 def

XVl/93/39/12/4 ^,/ 37,7 def

XVl/4 7 /59/63/40 /' 38, 1 .. _def

XIV 860554

-

^{38,2 def}

XIV 1992

-

^{39,9 ef g}

XIV /66/14/4/58 ^{,/ .} 41,3 efg

X/20,5/73/31 /45/78 ,/ 41,9 ef g

Kathmandu

-

_{... .} ·~ . ^{~· 42,? f g}

Snowball

-

^{43,0 f g}

xv

/25/5/87 /97 ^,/ 49,4 g

Table 3:

Nr

11 2 20 12 18 14 10 9 15 13 17 19 8 1 7 6 5 16 4

Egg counts in 1991 on caulifiower varieties and progenies selected for. resistance (/) or susceptibility ()') to cabbage root fly during the series of

odd years. ·

PLANT Mean number Significance

of cabbage root , fly eggs per pl~nt . XIV/4/32/56/18

.

'

^{2,8 a}

Vll/14/82/35/90

_.,

^: _{6,8 ab}

XIV ^{;... :} 8,4 abc

Xl.V/4/32/30/18

_.,

_{9,6 abc}

XIX/4/39

_.,

_{11,5 be}

XIV /4n8/17 /3.1

_.,

_{12,3 be}

Xlll/15/27 /33/90 ^,/ 12,6 be ·

Xlll/15/27 /33/81 ^,/ 12,8 be

XIV /4/78/17 /67 ^,/ 13,0 be·

XIV /4/78/92/30 ^,/ 13,2 be

xv

/1 /81 /32/18 ^,/ 13,2 be

x -

^{13,7 be}

Xlll/15/4/48/48 ^,/ 14,8 bed

111/16/98/54/46 ^,/ 14,8 bed

Xlll/15/4/48/83 ^,/ 15,3 ed

Xlll/8/32/18/42 . ^)' 22, 1 de

X/11/92/83/53 ^)' 22,7 e

XIV/14/18/50/3 ^)' 24,5 e

X/11/92/71/97 ^)' 28,9 e

. .

· Table 4: Cabbage root fly attack on some selected 1991 m~terial exposed to a high· fly population In the Valals In 1992. ·

Nr Variety I line RDI Significance

2-11 XIV /4/32/56/18 ^,/ 20,5 a

4-3 X/1 ·1 /56/82/7 ^,/ 21,5

a

3-2 Vll/14/82/35/90. ^,/ 25,9, ab

6-4 X/11/92/71/97

-

^{.I' ,26,5: ab}

1-20 XIV· 27,3 ab

5-16 XIV/14/18/50/3 .I' 29,5 b

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Figure 1: Seggregation In F4 between selected lines for resistance (---· XIV /4/32/56/18) and · susceptibility ( - - - XIV /14/18/50/3) . when compared with their common parent, the reference ( . XIV).