Pisum Genetics 

Volume 23

1991

Research Reports

pages 40-41

Additional mapping data for lum-2 on chromosome 3

Swiecicki, W.K.

and B. Wolko

Plant Experiment Station, Wiatrowo, 

62100  Wagrowiec, Poland

Swiecicki (2) described mutation cases of the costata type obtained at Wiatrowo. One of them was subsequently found (3) to be controlled by a gene, lum-2, which was strongly linked with M on chromosome 3 (Cr-0% = 2). Further linkage data are now available for lum-2 with two genes close to M: uni (Cr-0% = 4; Blixt 1977) and Lap-2 (Cr-0% = 9; Weeden 1985). Unfortunately, there was no suitable tester line available for multipoint analysis and additional difficulty was caused by the sterility of uni flowers (the mutant is maintained through heterozygous lines). In the first F2 population raised from the cross Wt15299 (lum-2 Lap-2s Uni) x Wt10187 (Lum-2 Lap-2f Uni/uni) segregation data were obtained only for alleles at the Lum-2 and Lap-2 loci. No uni segregates occurred (presumably no uni gametes were provided by the Wt10187 parent). The Cr-0 value for Lum-2 and Lap-2 was 17% in this cross and 15% in the F2 of cross Wt15299 (lum-2 Lap-2s) x Wt8905 (Lum-2 Lap-2f) (Table 1). In a second F2 population from cross Wt15299 x Wt10187 some families did segregate for uni. Small disturbances occurred in the monohybrid segregation but a strong deviation from independent assortment occurred for lum-2 and uni (Cr-0% = 12; Table 1). The following map is suggested based on our data and other results in the literature.

 

  1. Blixt, S. 1977. PNL 9 Suppl.

  2. Swiecicki, W.K. 1983. Hod. Rosl., Akl., Nas. 27(4): 221-276.

  3. Swiecicki, W.K. 1987. PNL 19:70-71.

  4. Weeden, N.F. 1985. In: The Pea Crop: A Basis for Improvement, Eds P.D.
    Hebblethwaite, M.C. Heath and T.C.K. Dawkins, Butterworths, Lond. pp 55-66.

Table 1. Phenotypic distribution in an F2 population from crosses:

1) Wt15299 (lum-2 Lap-2s)        x     Wt10187 (Lum-2 Lap-2f)

2) Wt15299 (lum-2 Uni)             x     Wt10187 (Lum-2 Uni/uni)

3) Wt15299 (lum-2 Lap-2s)        x     Wt8905 (Lum-2 Lap-2f)

A. Monohybrid segregation

Phenotype

Total

Chi-sq. (3:1)

1) Lum-2

lum-2

 

 

81

25

106

0.11

Lap-2f

Lap-2s

 

 

72

24

96

0.00

2) Lum-2

lum-2

 

 

244

53

297

8.11**

Uni

uni

 

 

202

95

297

7.73**

3) Lum-2

lum-2

 

 

110

21

131

5.62*

Lap-2f

Lap-2s

 

 

102

28

130

0.83

B. Joint segregation of lum-2 with Lap-2 and Uni

Phenotype

Total

Joint chi-sq.

Recomb. fract.

SE

Phase

1)Lum-2 Lap-2f

Lum-2 Lap-2s

lum-2 Lap-2f

lum-2 lap-2s

 

 

 

 

 

67

10

5

14

96

29.94***

17.1

4.3

C

2)Lum-2 Uni

Lum-2 uni

lum-2 Uni

lum-2 uni

 

 

 

 

 

149

95

53

1

297

27.84***

11.9

5.7

R

3)Lum-2 Lap-2f

Lum-2 Lap-2s

lum-2 Lap-2f

lum-2 Lap-2s

 

 

 

 

 

97

12

5

16

130

44.26***

14.9

3.4

C

*,**,*** P < 0.05, 0.01 and 0.001, respectively.

In segregating progenies, the phenotype designated Lap-2f includes both Lap-2f/Lap2f and
Lap-2f/Lap-2s plants.