Gene action for earliness, plant height and spike characteristics in wheat

Y.A. AL-SAHEAL and K.H. GAMIL

Botany Department, college of Science, University of Riyadh Riyadh, Saudi Arabia

The developmental of vigorous hybrid required a considerable time and efforts, thus, it is desirable to do estimation of heterosis and combining ability as earlier time of the breeding program. Moving target in the breeding procedure should be initiated by a good understanding of the mode of inheritance of quantitative genes affecting the desirable characters. The nature of genetic variability determines which type of selection will be the most effective in producing genetic advantageous. The variance due to average gene effects contributes fully to selection response whatever the type of selection applied. Genetic variance due to dominance and non-allelic interactions involving dominance are fully utilized in the future selection among F₁ crosses of homozygous lines but are completely nonexistant among the homozygous themselves.

This investigation based on five parent diallel cross. Such technique has been adopted extensively by many investigators in self and cross-pollinated crops in order to provide satisfactory introduction of the genetic mode of actions and genes that governing a particular quantitative characters. These studies have been commonly used with F₁ hybrids only.

This investigation was conducted to evaluate five parents and 10 F₁'s hybrids combinations in order to detect the amount of heterosis and combining ability in earliness, plant height and spike characteristics.

Materials and Methods

A diallel cross involving five cultivars of wheat from diverse regions were utilized in this investigation. These cultivars were: Super X (Mexican), Hinta Madeni (Local), Giza 155 (Egypt), Arz (Mexican) and one triticale called Arabian (Mexican).

10 F₁'s hybrids seeds (excluding reciprocals) along with five parents were planted in 1980 season in Jiffy pots (one seed per pot) and kept in the greenhouse. Three weeks later seedling were transplanted into the field after ideal preparation to the plots of land. The experiment were laid out at Faculty of Agriculture (Olisha), Riyadh University.

The experimental design was a randomized complete block with four replications. Each entry was represented by a row of 10 plants spaced 40 cms. apart and 30 cms. between rows.

Observations were recorded on five metric traits, namely days to heading, plant height (cm), spike length (cm), number of spikelets per spike and spike density.

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