Higher Fresh Root Research Articles

Influence of Autoclaved Fungal Materials on Spearmint (Mentha spicata L.) Growth, Morphogenesis, and Secondary Metabolism

The influence of autoclaved fungal materials such as culture filtrate, freeze-dried mycelium (FDM), mycelium suspension, and spore suspension (SS) on the growth, morphogenesis, and carvone production of spearmint (Mentha spicata L.) plants was studied. Fungal materials were either applied as a drench or spray on the plants. Spearmint plants (cv. "294099") drenched with SS (1 x 10(8) spores/ml) of Trichoderma reesei showed no significant differences in leaf numbers, root numbers, or shoot numbers compared with nontreated controls. However, significantly higher fresh weights and carvone levels were observed in plants drenched with T. reesei SS compared with the untreated controls. Fungal materials derived from Aspergillus sp., Fusarium graminearum, F. sporotrichoides, Penicillium sp., P. acculeatum, Rhizopus oryzae, and T. reesei were sprayed on spearmint foliage. F. graminearum, F. sporotrichoides, or R. oryzae elicited no enhanced growth, morphogenesis, or secondary metabolism responses. The best growth and morphogenesis responses were obtained employing Aspergillus sp., Penicillium sp., or T. reesei foliar sprays. For example, spearmint cv. "557807" plants sprayed with 100 mg/l FDM T. reesei isolate NRRL 11460 C30 stimulated higher fresh weights (75%), shoot numbers (39%), leaf numbers (57%), and root numbers (108%) compared with untreated plants. This effect was not dose-dependent because similar growth and morphogenesis responses were obtained by testing 10, 100, or 1000 mg/l FDM concentrations. Carvone levels in fungal-treated foliar-sprayed plants were comparable to nontreated controls. However, total carvone levels per plant were higher in fungal-treated plants because of their increased fresh weight.

Influence of mycorrhizal inoculation and different pruning regimes on fresh root yield of alley and sole cropped cassava (manihot esculenta crantz) in Nigeria

The effect of mycorrhizal fungus inoculation on fresh root yield of cassava (Manihot esculenta crantz) cv TMS 4 (2) 1425 as influenced by two hedgerow tree species and their mixtures, subjected to 2- and 3-month pruning regimes were investigated in alley cropping experiments at three different sites within the same eco-climatic region in Nigeria. Mixture of the prunings of the two hedgerow tree species (Gliricidia sepium and Senna siamea) with mycorrhiza gave higher fresh root yield than the sole hedgerow tree with mycorrhizal inoculation. Gliricidia sepium prunings were found to give higher fresh root yield than the prunings from the Senna siamea. The 2-month prunings of G. sepium recorded higher yield than its 3-month prunings while 2-month prunings of Senna siamea recorded higher yield than its 3-month prunings. However, mycorrhiza inoculation with 2- and 3-month prunings in the two hedgerow species used were found higher than their counterparts without mycorrhizal inoculation in all the three sites. Mycorrhizal inoculation without the hedgerow prunings recorded the lowest fresh root yield but was still higher than the fresh root yield from the sole without mycorrhizal inoculation. Thus, inoculation with mycorrhiza increased alley-cropped cassava fresh root yield over uninoculated plants under both pruning regimes. Generally, this study shows that inoculation of cassava with mycorrhiza alone without mulching with prunings significantly increased cassava fresh root yield.

Effects of cultivar and age at haverst on the dry matter, starch gelatinization properties and the cooking quality of cassava

The top-growth, root yield, dry matter and starch contents, swelling power, solubility and the pasting cycle of four cassava varieties harvested at monthly intervals from 7 to 13 months after planting were determined and related to the changes in cooking quality at the onset of the rainy season. The harvesting period coincided with the dry and part of the wet season. All four varieties lost their mealiness and poundability at the onset of the rainy season. Cassava root dry matter (RDMe) was the single most important factor which influenced the changes in cooking quality. The utilization of the stored carbohydrates for vegetative growth at the commencement of the wet season, possibly led to a great drop in RDMC which coincided with the seasonal loss in cooking quality. Local varieties went through the same changes but recovered faster than the introduced varieties. Total starch content did not explain the seasonal loss in cooking quality, but changes in some properties of the starch such as swelling power, solubility and gelatinization range could be related to the changes in cooking quality. Cultivars with high fresh root yield were not necessarily those with high dry matter and starch contents.