Foliar fertilization of soybeans (Glycine max (L.) Merr.) with N, P, K and S during the seed‐filling period promises to increase soybean yields. Such foliar applications could be used to avoid the depletion of these nutrients in the leaves and the resulting reduction in photosynthetic rate during this period due to poor nutrient uptake from the soil and translocation of these elements from the leaves to the developing seeds. Field experiments were conducted to test this hypothesis by spraying soybeans with solutions of N, P, K, and/or S in different proportions and at different times and rates. We supplied N primarily as urea, P primarily as poly‐phosphate, K with the P as potassium polyphosphate or with the S as potassium sulfate. Very significant yield increases were obtained from two to four sprayings on different soybean cultivars at different experimental sites between developmental stages R5 and R7. The optimum proportion of N:P:K:S in the solution 10:1:3:0.5. a proportion similar to that of these elements in the seeds. The optimum rate of total nutrient application was about 80 + 8 + 24 + 4 kg/ha of N + P + K + S, respectively. Yield increases were due to increases in numbers of harvestable seeds, not seed size. The results indicate that foliar fertilization during the seed‐filling period can become a very practical method for increasing soybean yields.

Common bean is recalcitrant to genetic transformation, due to limited regeneration capacity and low DNA transfer rates. The effect of different parameters on T-DNA transfer from Agrobacterium tumefaciens, was studied by measuring transient expression of the β-glucuronidase gene in Phaseolus vulgaris L. cv. CIAP7247F. Epicotyl containing seedling explants were inoculated with Agrobacterium EHA101 and C58C1Rif R (pMP90) strains harboring the binary vector pTJK136 with GusA gene on the T-DNA. Parameters studied were temperature and light regime during co-cultivation, explant injury, and the acetosyringone concentration for vir gene induction. The co-cultivation temperature and photoperiod had a significant effect on Agrobacterium DNA transfer. In addition, explant injury and supplementation of the cocultivation medium with acetosyringone increased the GUS activity. Optimal T-DNA transfer was obtained under the following conditions: co-cultivation at 25°C in darkness, injuring the explants with carborundum, and supplementation of the co-cultivation medium with 200 μM acetosyringone. This T-DNA delivery system was combined with a direct organogenesis protocol using epicotyl explants and fertile regenerants were recovered from tissue transformed with Agrobacterium. However, no transmission of transgenes to progeny could be observed, suggesting that the obtained plants were chimeras.

The incorporation of growth retardants (GR) such as ancymidol (ANC) or paclobutrazol (PBZ) in liquid culture media during multiplication stage of bananas decreases the excessive growth of stems and leaves. However, it is unknown if these chemicals have residual effect on further plant growth. To study the effect of ANC and PBZ on Grand Nain banana shoots, they were subcultured for five cycles in the multiplication stage and evaluated in elongation-rooting and acclimatization stages. Multiplication basal medium was Murashige and Skoog supplemented with 1.0 mg l )1 thiamine-HCl and 17.7 lM 6-benzylaminpurine (6-BAP), 9.75 lM ANC or 8.5 lM PBZ. Multiplied Grand Nain banana shoots were transferred to elongation-rooting stage and later on to ex-vitro conditions. The evaluation of GR residual effect and somaclonal variation on Grand Nain banana plants was determined through a comparative study of several morphological parameters in elongation-rooting and acclimatization stages. All morphological parameters evaluated in the elongation-rooting stage showed a similar performance with the exception of the pseudostem diameter of the vitroplants treated with both GR. There were significant differences for plant height in the acclimatization stage when shoots were multiplied in a medium containing ANC. The similarities of the parameters evaluated in both stages and the normal morphology recovery of vitroplants multiplied with PBZ suggest that there were no residual effects by adding PBZ to the culture media. The addition of ANC induced significant differences in plant height during the acclimatization stage.

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