Abstract
Two families each of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), corn (Zea mays L.), and bean (Phaseolus vulgaris L.) were studied for mitochondrial heterosis, in vitro complementation, and presence of hybrid-specific mitochondria using improved and standardized experimental procedures. Within each family, the inbred parents and their hybrids were compared for seedling height and rate of oxygen uptake by the whole tissue to establish if the hybrids show higher growth and respiratory activity at the seedling stage. Further comparisons were made by isolating mitochondria form seedling tissue and measuring their ADP:0 ratio, respiratory control ratio, and cytochrome c oxidase activity to examine mitochondrial heterosis of the hybrids. Mixtures of parental mitochondria were similarly compared with the parental and hybrid mitochondria for mitochondrial complementation. Mitochondrial types were studied by their sedimentation patterns by linear sucrose density gradient centrifugation. No evidence for mitochondrial heterosis, complementation, or presence of hybrid-specific mitochondria was found. Further, no correlation between the different mitochondrial parameters, seedling height, or oxygen uptake and their relationship with the hybrids could be established. The concept of mitochondrial heterosis resulting from mitochondrial interactions leading to heterotic expressions of growth and yield has been discussed. The possible application of mitochondrial heterosis and complementation for plant breeding has also been considered.
Sen, Dipankar (1973). An evaluation of mitochondrial heterosis and in vitro mitochondrial complementation in plants. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -157812.