02328nam a2200301 a 450000100080000000500110000800800410001910000240006024500590008426000350014330000100017850000200018852015430020865000130175165000120176465000130177665000140178965000170180365300240182065300270184465300210187165300240189265300230191665300160193965300250195565300220198065300240200213213572014-01-15       1986    bl uuuu  m   00u1 u    #d1 aTOLEDO, J. F. F. de  aBiometrical studies on inbred lines and their hybrids.  aUniversity of Birminghanc1986  a139p.  aTese Doutorado.  aThis thesis is divided into two parts. In the first part a method for prediciting the properties of second cycle hybrids produced by pairwise or diallel crossing of the first cycle recombinant inbred lines is described. Family means and variance of the P1, P2, F1 and F2 generations of a cross are all that is required for making these predictions. The predictions have been tested on two crosses derived from four varieties of Nicotiana rustica, viz. V1xV5 cross and V2xV12 cross. The data, results and discussions involving the V1xV5 cross are presented in three publications annexed as appendices, A, B and C at the end of the thesis. Results of the experiments conducted on the V2xV12 cross are discussed in detail in this part oh the thesis. The data collected from the basic generations (P1, P2, F1, F2, B1 and B2) of the V2xV12 cross raised in three environments were used for making the predictions and the F1 families of a 30x30 diallel produced from a random sample of first cycle inbred lines were utilized for testing their practical applicability. The main conclusion to emerge from the analyses and results is that the prediction procedures are reasonably robust. At first sight linkage disequilibrium, non-allelic interaction and genotype x environment interaction appear to complicate the procedures for making reliable predictions. While, however, they had some effects on the quantitative accuracy of the predicitons they did not, in general, invalidate them. The second cycle hybrids are of interest because amongst ...  abreeding  aEngland  agenetics  aGenética  aMelhoramento  aBiometrical studies  aCruzamentos dialelicos  aDiallel crossing  aEstudos biometricos  aGenetica de planta  aInglatuerra  aMetodos estatisticos  aNicoatian rustica  aStatistical methods