Efeitos da endogamia sobre a microsporogênese em milho-pipoca (Zea mays L.)

Abstract

The greatly appreciated popular popcorn has recently acquired great importance in the agronomic field and has been subjected to genetic improvement.Inbred lines are necessary for the formation of popcorn hybrids. Endogamy placesgenes for several characteristics in homozygosis, among which those related to the meiotic process. It may also cause several abnormalities that may affect the gametes viability. Current research aims at giving information on the meiotic stability of inbred lines of popcorn produced from a triple hybrid. It will be a contribution in the program on the production of highly productive hybrids. Original population (S0) and seven yearly self-fecundation generations (S1 to S7) were analyzed. Nine plants were analyzed for each genotype (S0 to S7) by the conventional meiotic studies methodology. Results were statistically compared by linear regression. The frequency of total and terminal chiasmata showed a progressive fall throughout endogamy whereas the frequency of interstitial chiasmata was not affected (p>0.05). Due to endogamy cells with meiotic abnormalities increased although their number was not very high. Since frequency of abnormalities was low and did not affect drastically the meiosis s final result, inbred lines from the hybrid under analysis may present a high potential for the production of new popcorn hybrids which should be adapted to the state of Paraná, Brazil.