Grain number per spike was studed in 6 winter wheat varieties and all their 30 direct and reciprocal F1 hybrids. Parents
included 4 released Romanian variety, the old american Atlas 66 and a dwarf breeding line, Oradea 79. This line has a low number of
grains/spike, but is important in breeding program for here reduced height. General and... specific combining abilities were computed and
genetic effects were estimated using Griffing’s method 1, model 1, as modified by Cabulea (1983).
For this diallel crosses, gene interactions and the interaction between cytoplasm and nuclear genes were highly significant and
the ratio of additive and non-additive effects was close to one.
The variety Fundulea 29 showed the highest general combining ability and it is recommended as a good parent for increasing
grain number/spike. Mid-parent heterosis was significant in 9 out of the 30 cases, mostly in hybrids involving the breeding line Oradea 79.
In 3 cases the number of grains/spike of F1 hybrids was significantly lower than the average of the parents. The breeding line Oradea 79 had
a significant negative general combining ability, but showed significant positive specific combining ability in most crosses, as well as a
significant positive effect of its cytoplasm. These results are considered to indicate that there are chances of improving the grain
number/spike in some crosses with Oradea 79.

We have analyzed the effect of grain maize and sunflower forecrop on three different winter wheat genotype (GK Csillag, Mv Csárdás, Mv Toldi) regarding to the spike number and yield in different fertilization levels in the 2012/2013 cropyear. According to our data after sunflower forecrop we reached higher spike number and yield, which were i...nfluenced by the differences of the varieties. We found significant differences between the varieties in the control treatment. According to our research, GK Csillag has reached the highest yield in the examined fertilization levels and forecrop models too.

The effect of major production factors (forecrop, fertilisation, irrigation, soil cultivation and soil preparation) on the yield components and yield of winter wheat were studied in a long-term  experiment set up at the Látókép Experimental Nursery of the Agricultural Sciences Centre of the University of Debrecen. The results of regress...ion analysis led to the following conclusions:
• In our experiments in 2000, after using maize as a forecrop –based on the results of analysis of regression – fertilisation determined the yield.
• After using pea as a forecrop, a N50 P35 K40 kg/ha fertiliser rate led to an economical increase in the yield of winter wheat.
• None of the determinative yield components varied significantly for winter wheat produced after using pea as a forecrop.
• There is a closed, significant correlation between plant height, spike length, plant and spike mass, the number of spikelets and grains per spike after using maize as forecrop. The thousand grain mass is different from the other yield components, because it is not part of the relation system of
those yield components.
• The increased yield of winter wheat after maize has been used as a forecrop is due to the positive change in grain number per spike yield component.