|
Pisum Genetics |
Volume 26 |
1994 |
Research Reports |
page 28 |
Additional information on the linkage of genes apu and uni of Pisum sativum L.
|
Sarala, K. and Sharma, B.
|
Indian Agricultural Research Institute New Delhi-110012, India |
There are only a few reports about the location of the apu (apulvinic) and uni (unifoliata) genes. Marx (1) reported linkage of apu and tac (tendrilled acacia) with gene st of linkage group III and a gene order of tac-apu-st while Marx et al (3) proved that apu and uni lie on the M side of st. Subsequently, Marx (2) showed tac was allelic with uni and Swiecicki (4) showed the apulvinic and petiolulatus mutants were allelic (4) f. The purpose of our study was to obtain additional information on the linkage of apu and uni.
In 1989-92, linkage of genes apu and unitac with gene st was studied in four crosses. Results were analysed using the joint segregation Chi-square to detect linkage and the product ratio method to calculate the recombination fraction.
The joint segregation analysis (Table 1) indicated that gene apu is located between st and uni in linkage group III with the map distances as follows:
These results are in agreement with those of Marx (1), who used the apulvinic line, and with the arrangement shown in the recent map of Pisum (5). Our calculated distance between apu and st is slightly larger than that shown on the latter map (15 versus 9 cM) but this difference is not statistically significant.
Table 1. F2 joint segregation data and recombination fractions for genes st, apu and unitac.
|
Loci |
Phase |
Cross |
Phenotype |
Total |
Joint c2 |
Recomb |
SE |
||||
|
XY |
Xy |
xY |
xy |
||||||||
|
Apu |
St |
Repul |
P 1297-2 x P 1426-2 |
64 |
27 |
28 |
1 |
120 |
8.45** |
19.6 |
8.7 |
|
|
|
|
P 1297-9 x P 1426-2 |
11 |
9 |
9 |
0 |
29 |
5.87* |
<24.2 |
- |
|
|
|
|
P 1297-11 x P 1426-2 |
17 |
7 |
11 |
0 |
35 |
4.01* |
<29.7 |
- |
|
|
|
|
Pooled data |
92 |
43 |
48 |
1 |
184 |
17.56*** |
14.5 |
7.2 |
|
|
|
|
Heterogeneity c2 |
|
|
|
|
|
0.77 |
|
|
|
Uni |
St |
Repul |
P 1297-2 x P 1426-2 |
66 |
27 |
25 |
2 |
120 |
5.34* |
28.2 |
8.3 |
|
|
|
|
P1426-2 x P 1297-1-21 |
519 |
188 |
194 |
16 |
917 |
33.69*** |
30.0 |
3.0 |
|
|
|
|
Pooled data |
585 |
215 |
219 |
18 |
1037 |
39.01*** |
29.8 |
2.8 |
|
|
|
|
Heterogeneity c2 |
|
|
|
|
|
0.02 |
|
|
|
Uni |
Apu |
Coupl |
P 1297-2 x P 1426-2 |
82 |
11 |
10 |
17 |
120 |
30.59*** |
20.2 |
4.2 |
*,**,***P<0.05, 0.01 and 0.0001, respectively
Marx, G.A. 1984. Pisum Newsl. 16:46-48.
Marx, G.A. 1986. Pisum Newsl. 18:49-52.
Marx, G.A., Weeden, N.F. and Provvidenti, R. 1985. Pisum Newsl. 17:57-60.
Swiecicki, W.K. 1990. Pisum Newsl. 22:66.
Weeden, N.F., Swiecicki, W.K., Ambrose, M.
and Timmerman, G.M. 1993. Pisum
Genetics 25:4 and cover.
*****
f Some confusion exists over the use of symbols uni/tac and apu/pet. The valid gene symbols are uni and apu. See Ambrose (Pisum Genetics 26:44,1994). Editor