Indian Journal of Genetics and Plant Breeding (The)

This paper records the results of an attempt to find out whether any metaxenia effect is observed on the fruits and seeds in Brassica crosses as has been reported by Singh (1957).

Data on fruit size, seed number, and seed weight were collected on females of autotetraploid toria under pollination conditions varying from complete assortative to complete random matings. It was expected that metaxenia, if present, should be manifest as varying relationship between fruit size and seed number measured in terms of correlation coefficients between the two characters.

Fruit size was found to be correlated with seed number with same magnitude and sign over all the different types of pollinations, the ‘r’ value being 0.4. This relationship was not disturbed by varying the male parent. No metaxenia effect was observed.

Seed number per fruit at maturity is highly correlated with ovule number counted on the day of flower opening. This leads to the conclusion that seed number and fruit size are both dependent on ovule number which is determined ontogenically the earliest and by the genotype of the mother. In individual cases genetically determined small-seededness might disturb the correlation between seed number and fruit size.

It is concluded that there is little scope for exploiting metaxenia phenomenon in increasing the seed yield in oil Brassicas.