The effect of spikelet position on the success frequencies of wheat haploid production using the maize cross system

Barbela is an old Portuguese landrace of wheat that is highly genetically h eterogeneous. Different Barbela populations when subjected to aluminium str ess show variable levels of tolerance. In order to study the inheritance of this character, doubled haploid (DH) lines were developed. These DH were o btained by intergeneric crosses of 14 different lines of Barbela with maize . During this process the efficiency of the technique was evaluated and sug gestions for its improvement were obtained. Several parameters were studied in the crosses: % of crossability, % of embryos per florets pollinated and % of embryos per seed set. The different genotypes of Barbela showed signi ficant variation for the parameters analysed. When the reciprocal crosses w ere analysed, no differences were found, indicating that cytoplasm differen ces do not influence the parameters of DH production. However, different sp ikelet positions (lower, middle and upper) gave highly significant differen ces in all parameters analysed. Highest success frequencies were obtained f or pollinated spikelets in the middle of the spike. This can indicate that concentrating on the middle part of the spike can increase the frequency of DHs obtained using intergeneric crosses of wheat with maize.