Plant Breeding Institute, Faculty of Agriculture, Hokkaido University, Sapporo, 060 Japan
In the tissue-culture experiments of rice, genotypic differences have been
recognized in the rate of callus formation and organ differentiation. We have
examined the effect of genic differences on morphological and physiological
traits of callus using two groups of isogenic lines: 17 dwarf lines of Shiokari
and 8 lines of Taichung 65 (T65) with different marker genes. The calli were
induced from dehulled seeds and were cultured on N6 medium supplemented with
4.4 mg/1 2,4-D, 50g/1 sucrose and 10g/1 agar. They were kept in the dark at 27
degrees C and were transferred to fresh media every 10 days. The diameter of
callus was measured at 50 days after seed plating.
The Shiokari dwarf lines exhibited a wide range of variation in callus diameter (Table 1). The lines having gene d-7 (cleistogamous dwarf) and sd-1 showed better callus growth than the recurrent parent Shiokari, while other isogenic lines showed inferior growth. On the other hand, the callus growth of T65 isogenic lines resembled that of T65 except T 65 fgl (faded green leaf) which showed the poorest growth. T65 g-1 (long sterile lemma) may be regarded as showing better callus growth than T65. Probably, some gene affecting morphogenesis may also influence callus growth.
Table 1. Callus diameter measured at 50 days after seed plating
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Isoline Marker diameter Isoline Marker Diameter
gene (mm) gene (mm)
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ID-s Shiokari 9.8 ID-42 d-42 4.6
ID-2 d-2 9.5 ID-51 d-51 9.1
ID-7 d-7 13.5 ID-52 d-52 6.5
ID-8 d-8 9.2 ID-47 sd-1 12.0
ID-10 d-10 6.8
ID-12 d-12 6.7 T-65 Taichung 65 10.5
ID-13 d-13 11.1 T65g-1 g-1 12.4
ID-15 d-15 5.3 T65pg-1 pg1 11.0
ID-17 d-17 5.2 T65Dn-1 Dn-1 11.0
ID-18h d-18h 6.2 T65Cl Cl 10.4
ID-18k d-18k 6.9 T65d1 dl 9.8
ID-19 d-19 6.0 T65wx wx 9.6
ID-27 d-27 5.9 T65gl-1 gl-1 9.4
ID-35 d-35 4.4 T65fgl fgl 3.5
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