Pollination and cytoplasmic effects on total dry weight

In 1983 (MNL 57:10-11), pollination and cytoplasmic effects for a single cross, including the reciprocal, were described. These hybrids were opaque, semident and middle cycle. The present work has two purposes: 1) To confirm reciprocal effects in long cycle hybrids; 2) To establish if there is a similar performance between the F1 and the F2 of three-way crosses, which are different in their cytoplasms.

The material was: a) the F1 single cross, (AxB) direct cross and the reciprocal (BxA); these hybrids were opaque, flint and long cycle; b) two sets of three-way crosses obtained from these single crosses and three opaque dent inbred lines, 1, 2 and 3:
(AxB)x1   (BxA)x1
(AxB)x2 and (BxA)x2
(AxB)x3   (BxA)x3

Both classes of single cross plants were: 1) not pollinated; 2) self-pollinated; 3) pollinated with three inbred lines, 1, 2, and 3; and 4) pollinated with each parent line, A and B. Both sets of three-way crosses were: 1) not pollinated and 2) self-pollinated. The experimental design was "randomized plots" of 15 replications (one plot for all classes of material and types of pollination, 30 plants per plot). For each plant 5 parameters were measured, but in this paper we analysed one parameter only: total dry weight/plant.

Results were as follows (Table 1):

1) Systematically, the reciprocal cross was better than the direct cross for all types of pollination:

(AxB) < (BxA), **P<0.01

2) There is a positive correlation (* P<0.05) between the F1 and the F2 in both sets of three-way crosses:

(AxB)x1 > (AxB)x2 > (AxB)x3


r = 0.969 * P<0.05

(BxA)x1 > (BxA)x3 > (BxA)x2


r = 0.987 P<0.05

Thus we conclude: 1) There are reciprocal effects on total dry weight/plant in this single cross; 2) For both sets of three-way crosses, we notice that the F1 (progeny of crossing with the inbred lines) and the F2 (progeny of self-pollination) have the same sequence of yield.

Table 1. Means of total dry weight/plant for all materials and treatments (g).

P. Fontanet, A. Alvarez and M. Blanco

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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