INHERITANCE OF LEMMA COLOR, SEED COLOR AND PANICLE FORM AMONG FOUR CULTIVARS OF ERAGROSTIS TEF (ZUCC.) TROTTER

Basic genetic information needed for a well-planned and rapid teff improvement program is lacking. The purpose of this investigation was to provide part of that missing information by determining the inheritance of: lemma color, seed color and panicle form. The objectives were to determine: (1)the gene actions and interactions, (2)the number of genes involved, (3)the presence or absence of maternal effects, (4)the presence or absence of linkage and (5)the kind of tetraploidy in teff. Six crosses were made among four cultivars - Fesho, Bursa, Kay Murri and Trotteriana. These cultivars have contrasting phenotypic characteristics. Fesho has purple lemmas, dark-brown seeds and very loose, multilaterally oriented panicle branches. Bursa has gray lemmas, greyish-white seeds and fairly loose, unilaterally oriented panicle branches. Kay Murri and Trotteriana both have compact and multilaterally oriented panicle branches. Kay Murri has red lemmas and yellowish-white seeds while Trotteriana has yellowish white lemmas and medium-brown seeds. Data were collected on individually transplanted plants and their progenies in the first (F(,1)), second (F(,2)), third (F(,3)) and backcross generations. Thirty-six F(,1) and 559 backcross plants were grown in individual pots in the greenhouse while 3,600 F(,2) plants were grown in the field. A greenhouse winter nursery was used to grow 9,600 F(,3) progenies in two soil beds. The investigation was conducted at the Lincoln and Scottsbluff experimental stations of the University of Nebraska-Lincoln during 1978-80. Results of the inheritance of lemma color showed that four pairs of genes were involved. This was demonstrated by F(,2) segregation ratios of 3:1, 12:3:1, 15:1, 45:3:16 and 180:12:48:16. Dominance, complementary and epistatic gene action and interactions were found. The four cultivars were assigned the following genotypes: Fesho (purple) = CCPPP2P2GG, Bursa (grey) = ccPPP2P2GG, Kay Murri (red) = CCppp2p2gg and Trotteriana (yellowish-white) = ccPPP2P2gg. Duplicate pairs of genes were identified for the inheritance of seed color. B2 and B were assigned for brown seed color genes and b and b2 for their corresponding alleles for white seed. Gene action between the genes and their alleles was simple dominance with additive effects. Fesho (dark-brown) produced an F(,2) ratio of 15 brown:1 white when crossed with Kay Murri (yellowish-white) and Bursa (greyish-white), whereas the result was 3 brown:1 white for crosses with Trotteriana (medium-brown). Therefore, the seed color genotypes of the parents were determined to be Fesho = BBB2B2, Trotteriana = BBb2(\u27gy)b2(\u27gy), Bursa = bbb2(\u27gy)b2(\u27gy) and Kay Murri bbb2b2(\u27.) Panicle form was found to be conditioned by duplicate pairs of genes for degree of looseness and another pair of genes for branching pattern. Segregation ratios of 15 loose:1 compact in loose x compact crosses showed duplicate dominance for gene action. Loose x loose crosses were all loose and compact x compact crosses were all compact. On the other hand, F(,2) segregation ratio of 13 multilateral:3 unilateral for branching pattern suggested a recessive suppressor types of gene action. Only the cultivar Bursa was found to have unilateral branching. The terms, effusum (very loose, multilateral), contractum (fairly loose, unilateral) and compactum (compact, multilateral) were adopted to include both aspects of panicle form. Fesho (effusum) was assigned a PaPaPa2Pa2 genotype for looseness and MbMbsusu for multiple branching. Similarly, the others would be: Bursa = PaPaPa2Pa2 mbmbSuSu, Kay Murri = papapa2pa2 MbMbsusu and Trotteriana = papapa2pa2 MbMbsusu. No maternal effects or linkages were detected. All the results showed a disomic inheritance pattern for all three traits which indicates that teff is an allotetraploid. This, in turn, indicates that quantitative genetic theory developed for diploids is applicable to teff