PART I RESEARCH NOTES Achkova-Valkova, Z., and P. Stoeva Bilate- The utilization of L. peruvianum as a female ral hybridization of Lycopersicon eru- parent with self-compatible species from the vianum Mill. with some self-compatible genus Lycopersicon will give the opportunity species. (Submitted by C. Daskaloff) to study the interaction of its cytoplasm with the genomes of these species. When the hy- bridization  is  done  at  a  diploid  level,  L.  peruvianum  manifests  considerable  or  full  reproductive isolation.   That's   why   hybridization   at   heteroploid   level   with   three   self-compatible   species manifesting   certain   instability   in   their   interspecific   reproductive   relations   -   L.   hirsutum   f. glabratum, L. minitum and S. pennellii (Atico) - has been applied. The  hybridization  has  been  carried  out  in  the  greenhouse  in  two  directions  so  that  each parent  takes  part  as  an  autotetraploid  and  a  diploid.  An  indispensable  condition  for  successful hybridization is the use of unemasculated buds. In order to preclude self pollination, about 24 h after the pollination the bared stigma has been covered with a layer of dextrine glue. The hybrid character of the plants has been determined by the chromosome number (2n=36) and some marked characteristics. Hybrid   seeds   have   been   obtained   from   the   two   directions   of   crossing  on  condition  that  L. peruvianum  takes  part  as  a  diploid  and  its  partner  as  a  tetraploid.  While  the  hybridization  with  L. minutum  and  S.  pennellii  is  relatively  easy  (18.9  -  25.7  hybrid  plants  per  100  pollinated  buds) hybridization with L. hirsutum f. glabratum is  very  difficult  (2.1  - 2.4 hybrid plants per 100 pollinated buds).  Phenotypically  the  sesquidiploids  are  diverted  strongly  towards  the  tetraploid  parent.  The fertility reaches up to 58%. The sesquidiploid L. peruvianum (2n) X L. hirsutum f. glabratum (4n) was the first to be used for a bridge  between  L.  peruvianum  and  other  species  because  the  work  with  it  began  earlier.  The obtaining  of  F2  and  BC1  was  difficult.  From  230  crosses  with  L.  hirsutum  f.  glabratum  2  aneuploid plants with 25 and 26 chromosomes were obtained. The second backcross was easily obtained. The   plants   from   BC1  with   L.  hirsutum   f.  glabratum  failed   to   cross   with   L.  esculentum  but   in hybridization with L. pimpinellifolium from 147 pollinated buds 75 plants were obtained. Their hybrid character was determined by the orange color of the fruits. F1 of this complex hybrid was crossed easily  with  L.  esculentum  (from  213  pollinated  buds  -  157  hybrid  plants).  The  fruits  of  the  new hybrid were red- or orange-colored with intermediate inheritance of fruit size. Via the sesquidiploid L. peruvianum (2n) X L. hirsutum f. glabratum (4n) have been obtained BC with L.  esculentum.  With  the  progress  of  the  backcrosses  in  the  first  two  cases  an  increasing  of  pollen fertility has been observed. These data suggest that the appearance of cytoplasmic male sterility can hardly be expected. It is too early to speak about certain phenotypic manifestations of the combination between the cytoplasm of L. peruvianum and the genomes of L. esculentum. The  work  for  hybridization  of  L.  peruvianum with L. esculentum was  done  in  the  period  from the  end  of  1974  'til  the  middle  of  1977.  This  characterizes  the  method  as  relatively  quick  and efficient in investigation of the interrelations of the cytoplasm of L. peruvianum and the genomes of the self-compatible species from the genus Lycopersicon. Allavena, A., and G. P. Soressi Tetraploid Tetraploid seeds from hand-pollination of parthenocarpic fruitful tomatoes. polyploid shoots following colchicine treat- ment (0.5% emulsion) of pat/pat F3 seedlings have been obtained. These self-fertilized seeds produced 4N parthenocarpic plants as fruitful as the corresponding  diploids.  On  the  contrary  the  4N  homozygous  pat+  plants  were  almost  completely sterile. Besides the 4N parthenocarpic fruits  were larger and heavier (30%) than the corresponding 2N. In addition their soluble solids and pH did not significantly differ from the diploid pat/pat, while the ascorbic acid content was higher (20%). As the tetraploid tomatoes have not so far proved to be of economic  importance  mainly  because  of  their  reduced  fertility,  our  data  put  in  evidence  the potential of the polyploidy coupled with the parthenocarpy in tomato breeding.

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