302 



LEROY POWERS 



In this same study (Powers, 1936) found that the greater the number of 

 genes in the genotype tending to increase a character the greater is the effect 

 of any given gene. It is apparent that it is not possible to definitely predict 

 the yield of seed per plant resulting from recombining genes favorable to 

 growth because of the interactions noted. Either a greater or smaller increase 

 than expected may be obtained. Such interactions of genes would affect the 

 yield of plants in which the favorable genes were recombined, and hence the 

 feasibility of obtaining inbred lines equaling or excelling the Fi hybrid. In 

 some cases the probability of getting the desired results would be increased 

 and in other cases decreased; depending on the type of interallelic and intra- 

 allelic interactions of the genes. 



GENE RECOMBINATIONS DIFFERENTIATING WEIGHT PER LOCULE 

 WHICH EXCEED HETEROSIS OF F, POPULATION 



The data for weight per locule of fruit for the Porter X Ponderosa to- 

 mato hybrid and parental populations grown at Woodward, Oklahoma, in 



TABLE 19.4 



.ARITHMETIC AND LOGARITHMIC MEANS FOR 

 WEIGHT PER LOCUI.E OF PORTER X PONDERO- 

 SA TOMATO HYBRID AND PARENTAL POPULA- 

 TIONS* 



* Grown at Woodward, Oklahoma, in 1041; original data taken in grams 

 and transformed to logarithms to obtain the means and standard errors of the 

 logarithms. 



1941 (Powers, Locke, and Garrett, 1950) will be analyzed to determine 

 whether in Fo and backcross populations gene recombinations are occurring 

 which exceed the heterosis of the Fi population. 



The means for weight per locule calculated on both the arithmetic and 

 logarithmic scales are given in Table 19.4. Weight per locule is greatest for 

 the Fi population, and the means of the Bi to Porter, F2, and Bi to Ponderosa 

 populations are larger than the means of the Ponderosa and Porter parents, 

 but smaller than the mean of the Fi population. The only means not showing 

 significant differences are the means of Porter and Ponderosa, and the means 

 of the F2 and Bi to Ponderosa populations. Hence, in these hybrid popula- 

 tions weight per locule definitely shows heterosis on either scale. 



