Inheritance of internode and culm length in hexaploid Triticale

Summary A diallel cross of twelve cultivars of hexaploid Triticale was made in order to study genie action types for total culm length and for the length of its different segments. Culm length, and four partial lengths of the culm were studied in the F₁ and F₂ generations. The analysis was made according to the Griffing, Hayman and Jinks models. Heterosis in culm length is mainly due to its upper half. Spanish cultivars have, in general, positive GCA and transmit greater height in crosses, whereas the Mexican ones show a negative GCA effect and have a tendency to decrease in height when crossed. Additivity greatly influences the inheritance of culm length, this influence being lower at the first plant internodes. The environmental component has also a large influence in the phenotypic expression of Triticale height. Dominance is only partial for the five traits studied. The predominant kind of interaction seems to be of the duplicate type. All correlations between culm length and its components are high and positive, especially the genetic ones.     

Molecular cytogenetic analyses of hexaploid lines spontaneously appearing in octoploid Triticale

Genome characterization of 14 hexaploid lines that spontaneously appeared in octoploid Triticales was carried out by sequential genomic in situ hybridization and fluorescence in situ hybridization, high molecular weight glutenin subunits and SSR marker analyses. All of the lines showed a chromosome constitution of complete A and B genomes, and a composite genome consisting of the chromosomes of D and R genomes. The composite genome of the 11 lines consisted of chromosomes 1R, 2D, 3R, 4R, 5R, 6R and 7R, that of the two lines were 1D, 2D, 3R, 4R, 5R, 6R and 7R, and that of one line was 1R, 2D, 3R, 4R, 5R, 6D and 7R. The incompatibility of the D and R genomes in common wheat genetic background, preferential retention of chromosome 2D and importance of these lines for the development of hexaploid Triticale are discussed in this report.     

Longevity of cryogenically stored seeds

Though cryogenic storage is presumed to provide nearly infinite longevity to cells, the actual shelf life achieved under ultra-cold temperatures has not been addressed theoretically or empirically. Here, we report measurable changes in germination of dried seeds stored under liquid nitrogen conditions for >10 years. There was considerable variability in the extent of deterioration among species and accessions within a species. Aging time courses for lettuce seeds stored at temperatures between 50 and -196 degrees C were fit to a form of the Avrami equation to determine rate coefficients and predict half-life of accessions. A reduction in the temperature dependency on aging rate, determined as a break in the Arrhenius plot, occurred at about -15 degrees C, and this resulted in faster deterioration than anticipated from extrapolation of kinetics measured at higher temperatures. The break in Arrhenius behavior occurred at temperatures in between the glass transition temperature (28 degrees C) and the Kauzmann temperature (-42 degrees C) and also coincided with a major triacylglycerol phase change (-40 to -7 degrees C). In spite of the faster than anticipated deterioration, cryogenic storage clearly prolonged shelf life of lettuce seeds with half-lives projected as approximately 500 and approximately 3400 years for fresh lettuce seeds stored in the vapor and liquid phases of liquid nitrogen, respectively. The benefit of low temperature storage (-18 or -135 degrees C) on seed longevity was progressively lost if seeds were first stored at 5 degrees C. Collectively, these results demonstrate that lowering storage temperature progressively increases longevity of seeds. However, cryogenic temperatures were not sufficient to stop deterioration, especially if initial stages of aging were allowed to progress at higher storage temperatures. This work contributes to reliable assessments of the potential benefit and cost of different genebanking strategies.     

Diallel analysis of androgenetic plant production in hexaploid Triticale (X. triticosecale,Wittmack)

Summary Studies were made on the genetic determination of androgenetic plant yield and its two components: embryo production and green plant regeneration. This involved the analysis of a complete 7×7 diallel cross of 4 androgenetic lines and 3 lines obtained by pedigree selection, one of them having the Triticum timopheevi cytoplasm. The three traits analysed are both heritable and environmentally influenced (by season and culture medium composition). The analysis of embryo production shows a mainly nuclear inheritance, with predominantly additive gene action, but also a favourable effect of Triticum timopheevi cytoplasm. Green plant regeneration has a more complex genetic determination, with additive as well as non-additive gene action and cytoplasmic influences. Hybrids appear superior to inbred lines for embryogenesis and green plant yield, but not for green plant regeneration. Androgenetic lines used as parents did not show superiority over other parents either in their own value or in the transmission of androgenetic abilities. Genetic improvement seems to be possible by recombination in progenies of hybrids between lines having complementary abilities.     

Moniliformin Accumulation in Kernels of Triticale Accessions Inoculated with Fusarium avenaceum, in Poland

Twelve Polish winter triticale cultivars and 14 doubled haploid lines (DH) (derived from the cv. Lasko × line SZD 366 hybrids) were inoculated with Fusarium avenaceum isolate ATCC 64451, mycotoxin moniliformin (MON) producer to evaluate their susceptibility to Fusarium head blight (FHB). Chemical analysis revealed MON accumulation in kernels of all inoculated cultivars in three consecutive years with the following averages and ranges: 1.50 mg/kg (0.47–2.67 mg/kg) in 1996, 2.63 mg/kg (0.11–8.14 mg/kg) in 1997 and 0.25 mg/kg (0.07–0.47 mg/kg) in 1998. Cultivar Malno kernels accumulated a low level of MON in all 3 years of the experiment. In most of the genotypes examined the reaction to the pathogen and MON content changed significantly from season to season. DH lines accumulated on average 2.62 and 0.85 mg/kg of MON in 1997 and 1998, respectively. Yield parameter reductions (1000 kernel weight, kernel number per head and kernel weight per head) were higher in 1997 than in 1998. The correlation coefficient for MON content/ Fusarium damaged kernels percentage was 0.539 in cultivars and 0.548 in the DH lines. This is the first report of FHB of a segregating population in triticale.     

Relations between Photosynthetic Pigment Accumulation and Microsporogenesis in Secale, Triticale, and Secalotriticum

The accumulation of photosynthetic pigments in underflag and flag leaves as well as the process of microsporogenesis in lines of tetraploid Secale, hexaploid Triticale, and hexaploid Secalotriticum were studied. Significant positive correlations were found between the amounts of chlorophyll a (Chl a), carotenoids (Car), Chl a/b ratio, and the normal proceeding of meiosis. High probability of paternal type of inheritance of specifities of meiosis of pollen mother cells and variation in photosynthetic pigments during plant transition from the stalk-shooting to heading stage were demonstrated.     

Retrieval of stored seeds by Marsh Tits Parus palustris in the field

The retrieval of stored food by Marsh Tits was documented using Hall-plate detectors to register visits to storage sites by marked individuals. In each experimental session a marked bird was allowed to store up to 50 radioactively labelled half-peanuts. By placing detectors next to each stored item that we located it was possible to show that birds attempt to retrieve about 25% of their stored food. Most of the retrieval is within one or two days (confirming Cowie et al. 1981) and the proportion of recorded retrieval attempts that are successful declines to zero after about three days. By this time storage sites have already been emptied by cache robbers. There may be a tendency for retrieval to occur in the afternoon.     

Significant contribution of boron stored in seeds to initial growth of rice seedlings

Rice plants are relatively insensitive to low boron environment. We examined the role of boron stored in seeds in growth of rice seedlings in regard to its insensitivity to low boron condition. In experiments using seeds without the removal of the endosperm, the effect of low boron treatments (0.18 and 0.03 μM B) was not evident on growth of seedlings until 5 weeks from germination. Analysis of boron distribution among different organs in rice grain demonstrated that the endosperm contained 92% of total boron in brown rice and husks contained twice as much boron as the brown rice. To examine the role of boron stored in the endosperm, endosperm were removed 5 days after de-husking and imbibition and the plants were subjected to boron treatments. The growth of the plants without endosperm was much reduced after 10 days under the 0.03 μM boron compared with the plants grown with the normal level (18 μM B). With the normal level of boron supply, the growth did not differ between the plants with and without endosperm, suggesting that growth difference between seedlings with and without endosperm under low B condition is not due to lack of starch or proteins, but due to lack of boron stored in seeds. Tracer experiments confirmed that a substantial amount of B was supplied from the seed to the seedling and that B limitation increased the B supply from seeds to seedlings, especially to roots. Our results established that boron stored in seeds, principally in the endosperm, contributes significantly to the growth of rice seedlings when external boron supply is limited.     

Incidence of mites associated with stored seeds and food products in upper Egypt

A survey on mites associated with stored seeds, flour and foodstuffs in Fayoum Governorate, Upper Egypt, proved the occurrence of about 24 species. Of these, 15 species in 8 families belong to Prostigmata, 6 species in 3 families belong to Astigmata and 3 species in 2 families belong to Mesostigmata.Members of the families Cheyletidae and Acaridae were the most common mites, found in many samples. Those of Caligonellidae, Ascidae and Raphignathidae were fairly common, but occurred in fewer types of samples. No mites were found in samples of lupine and camomile.     

Differential leakage of intracellular substances from imbibing soybean seeds

Leakage of electrolytes, substances absorbing UV light, and enzymic activities from imbibing soybean (Glycine max [L.] Merr.) seeds were compared to determine the extent that passive diffusion and cellular rupture contribute to each. Imbibing seeds with testae removed had average Arrhenius energies of activation (5 to 25°C) of 3.0 and 15.8 kilocalories per mole, respectively, for the leakage of electrolytes and embryo malate dehydrogenase activity. Leakage of embryo enzymes from imbibing seeds was dependent on loss of testa integrity and subsequent loss of cellular membrane integrity or inability to seal preexisting membrane discontinuities. These data suggest that electrolyte leakage from imbibing seeds is primarily by passive diffusion, whereas the diffusion of intracellular macromolecules is primarily dependent on physiological phenomena affecting membrane integrity. Kinetic data and examination of the composition of seed leachates indicated that the leakage of substances absorbing UV light during imbibition is due to both passive diffusion of low molecular weight solutes and macromolecules released from ruptured cells.     

Expression of circaseptan and circannual rhythmicity in the imbibition of dry stored bean seeds

Water uptake of seeds of Phaseolus vulgaris L. cv Limburg was monitored in a controlled atmosphere every day at solar noon for a period of 2 years. The imbibition rate, determined as the mean of five replicas, was related to the lunar cycle, maximal water uptake occurring between the new phases of the cycle. The monthly mean value of imbibition rate, calculated from the daily measurements, displayed a circannual rhythm reaching maximal values in August-September and minimal values in February-March. These monthly values were positively correlated with the mean of the maximal temperatures recorded daily outside.     

Improving germination and vigour of aged and stored onion seeds by matriconditioning

Germination and vigour of accelerated aged (AA) and naturally stored onion seeds were examined. Accelerated ageing was conducted at 40 °C and 100 % relative humidity (RH). Non aged seeds were stored for 34 months at 3 or 15 °C and 40, 60 or 90 % RH. To restore seed viability, stored and aged seeds were matriconditioned with Micro-Cel E. A distinct loss of germination was observed after 5 days of accelerated ageing. Naturally stored seeds maintained high viability for 34 months, when stored at 3 °C and 40, 60 and 90 % RH or at 15 °C and 40 %. An increase of RH to 60 and 90 % at 15 °C caused loss of germination and vigour. Matriconditioning improved germination and increased endogenic ethylene release and in vivo ACC oxidase activity of both aged and stored seeds.     

Accumulation pattern of arachin and its subunits in maturation of groundnut seeds

The accumulation pattern of arachin and its subunits in growinggroundnuts was investigated. Soluble proteins were extractedfrom the kernels at twelve different stages of maturation (4–16weeks after pegging). Fractionation showed arachin, conarachinII, 5S and 2S protein components with sucrose gradient centrifugation.Ten weeks after pegging, only 35% of the maximum amount of arachinhad accumulated, whereas conarachin II was 85%, the 5S component89%, and the 2S component 76%. Arachin, however, increased rapidlyin the later stage of maturation. No change in the subunit ratioin arachin during seed growth was observed on the patterns ofsodium dodecyl sulfate-gel electrophoresis and gel isoelectricfocusing in the presence of urea. The ratio of the arachin subunitscontained in urea-extractable fraction of the kernels was constantthroughout seed development and was consistent with the subunitratio in arachin. On the other hand, the arachin subunits inthe free forms, if any, accounted for less than 1% of the associatedarachin subunits. Probably, the arachin subunits synthesizedin equimoles are associated into arachin without individualdeposition and are accumulated as arachin associates in growingseeds. (Received July 17, 1980; )     

Accumulation pattern of arachin and its subunits in maturation of groundnut seeds

The accumulation pattern of arachin and its subunits in growinggroundnuts was investigated. Soluble proteins were extractedfrom the kernels at twelve different stages of maturation (4–16weeks after pegging). Fractionation showed arachin, conarachinII, 5S and 2S protein components with sucrose gradient centrifugation.Ten weeks after pegging, only 35% of the maximum amount of arachinhad accumulated, whereas conarachin II was 85%, the 5S component89%, and the 2S component 76%. Arachin, however, increased rapidlyin the later stage of maturation. No change in the subunit ratioin arachin during seed growth was observed on the patterns ofsodium dodecyl sulfate-gel electrophoresis and gel isoelectricfocusing in the presence of urea. The ratio of the arachin subunitscontained in urea-extractable fraction of the kernels was constantthroughout seed development and was consistent with the subunitratio in arachin. On the other hand, the arachin subunits inthe free forms, if any, accounted for less than 1% of the associatedarachin subunits. Probably, the arachin subunits synthesizedin equimoles are associated into arachin without individualdeposition and are accumulated as arachin associates in growingseeds. (Received July 17, 1980; )