Cross Breeding Technology In Cattleya Alliance

Cattleya Alliance is known as the “King of Orchid” with peculiar flower pattern and beautiful colors,and it is easy to cultivate owing to its good heat resistance and drought tolerance.It has a huge market potential because its ornamental character accords with the popular preference.Cattleya breeding started late in China,and there were few reports about it.Using Cattlianthe Doris and Byron ‘Christmas Rose’,Guaricattonia Red Tape ‘Cherry Beauty’,and Rhyncholaeliocattleya Village Chief North ‘Green Genus’ as meterials,we studied the cross compatibility,influencing factors of hybrid seed germination,elite strains selection from hybrid progeny,and rapid propagation of excellent cultivars in this paper.The results would contribute to the breeding and industrial development of Cattleya in China.The main results were as follows:1.The fruit setting rate of five culticars(‘Christmas Rose’,‘Cherry Beauty’,North‘Green Genus’,KTL4 and KTL20-2)of Cattleya hybrida greatly varied.Moreover,the reciprocal cross compatibility of the same variety was quite different.For example,KTL4,as a female parent,the fruit setting rate was as high as 100.0%,while as a male parent,the fruit setting rate was only 10.0%.Fruit age had a great influence on the germination of hybrid seeds in cross combination 18-104 because only the seeds with a fruit age of 50 days can germinate normally,and seed coat specialization may be an important factor which affected the germination of the hybrid seeds.Different medium had a great influence on the germination of hybrid seeds in cross combination 19-131.The effect of light on the germination of hybrid seeds in cross combination 19-140 was significant,and the germination rate was high.2.Among 38 cross combinations,the hybrid seeds in 21 combinations can germinate on different levels,and the seeds in other 17 combinations did not germinate at all.We selected one strain,16-52-18,which had strong differentiation ability and high survival rate of cluster buds,from hybrid combinations 16-52.In addition,we selected another strain,18-107-1,which had strong proliferation ability,more stem nodes and high survival rate,from combination 18-52.The two strains had the potential to become excellent new varieties due to the characteristics of rapid propagation.3.Sodium hypochlorite was better than mercuric chloride as the disinfectant of stem tip came from ‘Christmas Rose’,and the induction rate of protocorm-like bodies(PLBs)was 28.89%.The optimal medium for PLBs proliferation of ‘Christmas Rose’ was 1/2MS +CW 100 m L/L + sucrose 30 g/L + carrageenan 7 g/L.The most suitable medium for bud differentiation was MS + sucrose 30 g/L + carrageenan 7 g/L;the most suitable medium for seedling and root differentiation was Hyponex NO.1 + sucrose 30 g/L + carrageenan 7 g/L;and the most suitable medium for seedlings and rooting was Hyponex NO.1 + 6-BA 0.1mg/L + NAA 0.5 mg/L + potato juice 30 g/L + AC 0.2 mg/L + sucrose 30 g/L +carrageenan 7 g/L.Transplanted with mixed substrate of bark: peat soil: coconut bran = 1: 1:1 for 90 days,the survival rate of ‘Christmas Rose’ seedlings was 99.23%.Through the above research,we clarified the hybrid affinity of Cattleya,established the protocol of hybridization,seed germination,selection of elite strains from hybrid progenies and mass propogation of excellent varieties.As a result,we gained a large number of hybrid progeny and 2 elite strains,which laid a solid foundation for further breeding new varieties in Cattleya.