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The present study was undertaken to study the crossability barriers in interspecific crosses of Vigna radiata × Vigna umbellata. The basic materials of this experiment comprising of five mungbean MYMV Susceptible genotypes and five rice bean MYMV resistant genotypes. Interspecific crosses were attempted by utilizing rice bean genotypes as male parents and mungbean genotypes as female parents. The successful pod set was observed on 12 crosses out of 25 interspecific crosses of Vigna radiata and Vigna umbellata. The results revealed that highest crossability per cent was recorded in the crosses Yellowmung × KBR-1 (17.30 %), DGGV-2× RBL-35 (16.0%), Selection-4×KBR-1 (11.80%), Chinamung × KBR-1 (11.0%) and BGS-9× RBL-35 (10.20%) which were considered as successful crosses. This suggests that the parents of these four interspecific cross combinations may be ideal for transfer of useful genes across the two divergent species and to broaden the genetic base of interspecific hybrid and further, the existence of moderate hybrid pollen fertility (78.24%) coupled with moderate seed germination percentage (36.84%), lower hybrid lethality (21.43%) and lower hybrid breakdown (7.14%) was observed in Chinamung × KBR-1 followed by cross Selection-4 ×KBR-1. In the present investigation prominent observation noticed are strong pre-fertilization as well as post fertilization barriers were present in the cross between V. radiata and V. umbellata, while, growth and lethality of interspecific hybrid seedlings were influenced by the genotypes of both the parental species.

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N-Acetyl-~-D-muramic acid monohydrate, ClIH19NOa.H20, crystallizes in space group P212121 with a= 7.833 + 0"005, b= 8"084_+ 0.005, c= 23"495_+ 0"018/~ and Z=4. The structure was solved by direct methods and refined by least-squares calculations to R= 0.079 for 1060 observed reflections. The molecule has the 4C1 conformation with internal torsion angles ranging from 49 to 62 °. The C(1)-O(1)H bond (1.38_+ 0.01 A) is significantly shorter than the mean of four other single bonds. Ring C-O distances are 1-42 and 1"45 _+ 0-01 A for C(1)-O(5) and C(5)-O(5), respectively. An intramolecular hydrogen bond of 2.96/~ exists between the N-acetyl amide and the lactyl carbonyl. The resulting molecular conformation is unlike that proposed in earlier model studies which pointed to a similarity between penicillin and Nacetyl muramic acid as the basis for the activity of the antiboitic.

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