Time Of Tuber Initiation Research Articles

Metabolite analysis of tubers and leaves of two potato cultivars and their grafts.

Grafting experiments have shown that photoperiod-dependent induction of tuberisation in potato (Solanum tuberosum L.) is controlled by multiple overlapping signals, including mobile proteins, mRNAs, miRNAs and phytohormones. The effect of vegetative organs and tubers at metabolite level and vice versa, however, has not been studied in detail in potato. To unravel the influence of vegetative organs on the primary polar metabolite content of potato tubers and the effect of tuberisation on the metabolite content of leaves grafting experiments were carried out. Two potato cultivars, Hópehely (HP) and White Lady (WL), were homo- and hetero-grafted, and the effects of grafting were investigated in comparison to non-grafted controls. Non-targeted metabolite analysis using gas chromatography-mass spectrometry showed that the major difference between HP and WL tubers is in sucrose concentration. The sucrose level was higher in HP than in WL tubers and was not changed by grafting, suggesting that the sucrose concentration of tubers is genetically determined. The galactinol level was 8-fold higher in the WL leaves than in the HP leaves and, unlike the sucrose concentration of tubers, was altered by grafting. A positive correlation between the growth rate of the leaves and the time of tuber initiation was detected. The time of tuber initiation was delayed in the WL rootstocks by HP scions and shortened in the HP rootstocks by WL scions, supporting the previous finding that tuberisation is triggered by source-derived mobile signals.

Phenotypic analysis of tuber yield- and maturity-related traits in white yam (Dioscorea rotundata)

Inadequate yield potential of available varieties and their long growth periods are two of the factors limiting yam ( Dioscorea spp.) production. Identifying yield- and maturity-related traits and breeding for them will enhance production. Ten morphological/physiological traits: time of shoot emergence, time of tuber initiation, plant height, shoot dry weight, time of shoot senescence, tuber fresh weight (tuber yield), tuber number/plant, tuber parenchyma colour, tuber dry matter content and tuber dormancy period were assessed in eight accessions of D. rotundata (white Guinea yam) on the field in 2008 and 2009. Shoot dry weight and plant height were identified as the major tuber yield-related traits. Early field emergence and tuber initiation, short tuber dormancy period and low tuber dry matter content may also be related to tuber yield. High yielding accessions were low in tuber dry matter content. Moreover, early and late maturing accessions could be separated by time of attainment of uniform parenchyma colour within a tuber, length of tuber dormancy period and time of shoot senescence. Accessions were identified that may be used as parents for developing mapping populations for some of the traits assessed in the study. Key words: Dioscorea rotundata , tuber maturity, tuber dormancy, dry matter content, yield related traits, senescence.

Managing Volunteer Potato (Solanum tuberosum) in Field Corn with Mesotrione and Arthropod Herbivory

Volunteer potato is becoming increasingly detrimental in potato production regions. We assessed methods to manage the weed in field corn with herbicides and arthropod herbivory. In greenhouse trials, new tuber production was reduced at least 95% in ‘Ranger Russet’, ‘Russet Burbank’, ‘Russet Norkotah’, and ‘Shepody’ potato varieties by mesotrione applied at 0.11 kg/ha. In field studies conducted near Paterson, WA, a single application of mesotrione at 0.07 or 0.11 kg/ha applied at the time of tuber initiation (mid-postemergence [MPOST]) controlled potato top growth 96 to 98% in 2002 and 2003. Mesotrione applied at earlier stages of potato growth, preemergence or early postemergence, controlled potatoes less than mesotrione applied MPOST. All herbicide treatments prevented yield loss in field corn compared with nontreated checks. Mesotrione reduced new potato tubers and tuber weight more than any other herbicide. Herbivory of volunteer potato by Colorado potato beetle reduced tuber number 21% and tuber density 23% in the absence of herbicides and appeared to further suppress the weed in combination with herbicides. Whereas treatments containing mesotrione were most effective against volunteer potato, arthropod herbivory supplemented weed suppression and may be an important component in reduced or low-input weed management systems.

Effects of soil- and foliar-applied phosphorus fertilizers on the potato (Solanum tuberosum) crop

Twenty-two field experiments in England, done between 1986 and 2000, tested the effects of phosphorus (P) fertilizers on number of tubers and tuber yield in Solanum tuberosum. Applying P fertilizer resulted in statistically significant increases in tuber yield in six experiments and the optimal P application rate ranged from c. 90 to 180 kg P/ha. Statistically significant increases in yield in response to application of P fertilizers were found only in soils that contained < 26 mg Olsen-P/l (< Index 3) and appeared to be associated with increases in ground cover. Statistically significant increases in the number of tubers in response to application of P fertilizer were found only in soils that contained < 16 mg Olsen-P/l (< Index 2) and appeared to be associated with an increase in ground cover by the time of tuber initiation (c. 5–6 week after planting). Each tonne of tuber fresh-weight yield was, on average, associated with removal of 0·39 kg P but regression analysis showed that this value increased as soil Olsen-P increased. Re-analysis of published data showed that whilst the probability of a response to P fertilizer and the optimum P application rate may have been overestimated, some statistically significant responses to P fertilizer did occur when Olsen-P was > 26 mg/l. The absence of yield responses on P Index 3 soils found in the current experiments was attributed to increased use of irrigation that may have increased the availability of soil P. Re-interpretation of data from long-term experiments showed that the agronomic benefits of increasing soil P status by applying more P than is removed by harvested crop parts, are small. Since large P residues, estimated by Olsen-P or degree of soil P saturation, are associated with desorption of P and consequent loss to drainage water it is inadvisable to increase soil P above Index 3. For these reasons, no P fertilizer is recommended for Index 4 soils, an amount equivalent to replacement is recommended for Index 3 soils but up to 110–130 kg P/ha should be applied to Index 0 soils. Applications of foliar P had no effect on number of tubers or tuber yield and this practice cannot be recommended.

EFFECTS OF CULTURE DENSITY ON GROWTH AND IN VITRO TUBERIZATION CAPACITY OF POTATO PLANTLETS

In vitro plantlets of four varieties of potato (Solanum tuberosum L.) were grown at different plant densities to study their effects on growth and microtuber yield. The responses of the cultivars to plant density, as expressed by changes in development characteristics, especially stem length and leaf area, were different. The time of tuber initiation was earlier at higher plantlet densities for all cultivars. The microtuber number per plantlet was not affected by the plantlet density. The highest number of well-sized (≯4 mm) microtubers per jar could be harvested from the higher plantlet densities (30–40 plantlets per jar). In addition to good yield, the microtubers were uniform in these treatments, so they appear to be economical.

Effects of Types and Duration of Weeds on Yield Parameters of Cocoyam (Xanthosoma saghtifolium)

Weeds reduce yields of all tropical crops significantly, and these effects vary with different species. Thus, the influence of time of weed control and types of weeds on yield parameters of cocoyams (Xanthosoma sagittifolium), a tropical tuber crop, was determined by two experiments conducted simultaneously. In one experiment, weeds were removed at different times during crop growth. In the other, different weed types were removed selectively to leave either one or two of the identified categories, namely grasses, broadleaves and sedges. The presence of weeds throughout the growth cycle of the crop reduced yields of cocoyams by 60 %. Removal of weeds at early growth stages produced greater yields than weeds were present beyond 18–22 weeks after planting. The presence of weeds at the time of tuber initiation had the greatest adverse effect on yield parameters. Weeds had a delaying but not an inhibitory effect on cormel initiation. However, all other yield parameters were reduced by weeds. Broadleaved weeds, which have similar growth patterns as cocoyams reduced yields to a greater extent than grasses. Sedges had no significant impact on cocoyams. The presence of grasses and broadleaves together reduced growth and yields of this crop to a greater extent than any other combination.

Potato ( Solanum spp.) in an isohyperthermic environment V. Intercropping with maize

Seven experiments were conducted at 14°N latitude and 150 m a.s.l. in the Philippines. Various maize plant populations, spatial planting configurations and planting time of maize (from 0 to 30 days after planting potato) were evaluated to assess their influence on light transmission to the intercropped potato and its effect on growth and yield of potato and maize. With synchronous planting of potato and maize, there was no shading of the potato for the first 25 days after planting ( dap) resulting in no advantage in rate or percentage emergence, time of tuber initiation and tuber number plant −1. Low levels of shading (less than 25% from 50 to 60 dap potato) did not improve per plant tuber yield in any experiment. Potato tuber yields were significantly reduced when the solar radiation levels reaching the potato canopy dropped to less than 10 MJ m −2 day −1 during the middle of the bulking period (50–60 dap). Maize pulations of 30 000 plants ha −1 in a planting configuration where maize rows were 1.2 to 2.4 m apart transmitted more than the critical light requirement of 10 MJ m −2 day −1. Maize at 43 000 plants ha −1, planted up to 20 dap potato, delayed shading of the intercropped potato but resulted in shade levels exceeding 50% from 55 dap potato, which detrimentally affected potato yields in two experiments, and to a lesser extent in a third experiment. Potato yields ranged from 16 to 23 t ha −1 for the monocropped and best intercropped treatments across all experiments. Maize populations of 30 000 plants ha −1 along with 56 000 potato plants ha −1 improved land-equivalent ratios up to 1.4.

Study on the inheritance of potato tuber yield by means of harvest index components and its consequences for choice of parental material

The inheritance of potato tuber yield was studied considering the seasonal course of harvest index. Harvests of several progenies and their parents were performed at intervals and fresh weight of foliage, underground stems, tubers and stolons was assessed. Tuber yield depends on the time of tuber initiation and the proportion of the assimilates allocated to the tubers, as reflected in the increase rate of harvest index. The time of tuber initiation of the progenies was associated with the time of tuber initiation of the earliest tuberizing parent. The mean increase rate of the harvest index of the progenies was in most cases equal to the mean values of parents, however in crosses combining early with late maturing parents the rate equaled the value of the maternal parent. Using these relations, differences in harvest index between progenies can be predicted with a high degree of precision by using the harvest index parameters of the parents. This estimated harvest index showed a fairly good correlation to tuber yield at mid-September and can be used in the prediction of the yield of the progeny. The use of the mid-parent value for this purpose is not suitable.

Effect of the timing and rate of nitrogen fertilization on the growth and recovery of fertilizer nitrogen within the potato (Solanum tuberosum L.) crop

The effect of the timing of N fertilizer application on the uptake and partitioning of N within the crop and the yield of tubers has been studied in two experiments. In 1985 either none, 8 or 12 g N m−2 was applied and in 1986 none, 12 or 18 g N m−2. Fertilizer N was applied either at planting, around the time of tuber initiation or half at planting and the remainder in four foliar sprays of urea during tuber bulking.15N-labelled fertilizer was applied to measure the recovery of fertilizer N in the crops.

Effect of physiological age on growth vigour of seed potatoes of two cultivars. 4. Influence of storage period and storage temperature on growth and yield in the field

The influence of storage period and temperature on growth and yield was investigated for 3 years in a field study with cvs. Jaerla and Desiree, stored at 4°C or 12°C, in darkness, as a part of a combined study on the effect of physiological age on growth vigour. The seed of cv. Jaerla proved to age more rapidly than that of cv. Desiree: ‘little potato’ occurred in Jaerla, but in Desiree only when seed had been stored at 12°C and planted late. The 4°C treatments emerged more rapidly, produced more stems per plant and the onset of senescence was earlier than the 12°C treatments. There was no difference in time of tuber initiation between the two treatments. There were usually more tubers per stem in the 12°C treatments. Final tuber yield of Jaerla 12°C was lower than that of Jaerla 4°C, but the difference was only statistically significant at early harvest. There was no difference in yield between Desiree 4°C and 12°C, except for the 2nd planting time in 1981, when the 12°C treatment yielded significantly less.

Variation in Properties of Starch in Cassava Varieties in Relation to Age of the Crop

AbstractCassava starch extracted from six varieties at different period of growth was examined for various physiochemical properties. The granule size increased in all the six varieties upto 6th month from time of tuber initiation and thereafter remained almost constant. The amylose content and reducing values did not vary much at different stages of growth. The swelling volume and swelling power of starch showed large variations particularly after 10th month. Such changes of four varieties were not noticed in other varieties. Associative binding forces of starch molecules largely determine the stability characteristics of starch under varied environmental conditions.

Response of four potato varieties to potassium fertilization in a seed growing area of eastern Idaho

A soil test value of 112 ppm K in the 0 to 8 in (0 to 20 cm) depth was sufficient to produce a 250 cwt/A (28 T/ha) yield with no response to K fertilization. With a 93 ppm soil test value, potassium fertilizer increased yields in all four varieties tested. These results were obtained from trials at two locations in a seed-growing area in eastern Idaho where soil tests indicated low potassium levels (90 to 100 ppm K). Russet Burbank, Targhee, Nampa, and Butte varieties were included in the study at one location and only Russet Burbank at the second location. Potassium fertilizer treatments included K2O rates of 0, 250, and 5001b/A (0, 280, and 560 kg/ha) for each of the two forms of potassium fertilizer (KC1 and K2SO4). At the time of tuber initiation, a petiole content of 7% K in Russet Burbank was sufficient to produce maximum yields while a petiole content less than 6% K was insufficient. Analysis of petiole samples taken during the season showed that the K content declined rapidly as the season progressed. Potassium chloride generally resulted in higher petiole K levels than did potassium sulfate. Varieties appeared to differ in petiole K levels.

The effects of the growth-regulating compounds methyl decanoate and 2, 3, 5-triiodobenzoic acid on potato tuber size

SummaryApplication of methyl decanoate to a potato crop about the time of tuber initiation reduced the total yield and the yield of tubers in the grade 2·5–5·5 cm though neither of these reductions were significant. However, application of 2,3,5-triiodobenzoic acid increased the yield of tubers 2·5–5·5 cm by up to 20% while having no significant effect on total tuber yield. This change in the tuber size distribution was due to a more even partition of photosynthate between tubers and not to an increase in the total number of tubers.

Irrigation as a Practical Means to Control Potato Common Scab (Streptomyces scabies)

SUMMARYIrrigation in 1970 at Gleadthorpe E.H.F. increased potato yields and, when given from the time of tuber initiation, controlled common scab on the susceptible cultivars King Edward, Majestic and Record. Pentland Crown had little scab with or without irrigation. It was the driest May and June since 1934 and there was already a soil moisture deficit (S.M.D.) of 1.8 in. (46 mm) at tuber initiation by King Edward and when water was first given. Subsequently irrigation at 0.6 in. (15 mm) or 0.8 in. (20 mm) S.M.D. was more effective than 1.5 in. (38 mm) or 2.25 in. (57 mm) S.M.D. in controlling scab, and more effective at 0.6 in. S.M.D. when maintained for 4 wk than for 2 wk.Irrigation at 0.6 in. S.M.D. for 4 wk increased the weight of premium (Table Grade) potatoes by respectively, 16, 12, 13 and 12 tons/acre (40, 30, 32.6 and 30 t/ha) for King Edward, Majestic, Record and Pentland Crown.Tubers developed slowly in unirrigated plots both in volume and in the rate that eyes separated. King Edwajd produced more tubers per plant than Majestic; irrigation did not increase tuber numbers.

The effect of CCC, nitrogen and potassium on the growth and yield of two varieties of potatoes

SUMMARYThe two experiments described here were the 3rd and 4th in a series of experiments investigating the effect of time of application of nitrogen and potassium on the growth and yield of potatoes.The effect of applying all the fertilizer nitrogen in the seed bed was compared with applying all the nitrogen at the time of tuber initiation or dividing the dressing between these times. Similar times of application were tested for potassium. CCC was applied after a leaf area index of 3 had been reached (on all but the no N treatments) in order to offset the tendency for late nitrogen to increase stem growth, but to avoid any tendency for CCC to depress yield by reducing leaf area indices (L) below an assumed optimum value of 3. These treatments were applied in separate experiments to a second early variety (Craig's Royal) and a maincrop variety (Pentland Dell), planted a month later.In both crops the response to nitrogen was large and delaying or splitting the application of nitrogen increased tuber yield compared with nitrogen applied in the seed bed. Responses to potassium were small, but there was a tendency for split applications to be superior to late or early applications.The beneficial effect of delayed or split applications of nitrogen was associated with an improvement in the recovery of nitrogen in the crop which was largely ascribed to a reduction in loss due to leaching. Total and tuber dry-matter yields were linearly related to leaf area duration (D) in both crops, although the earlier variety was more efficient per unit of D. High values of L (6) were recorded for both crops, but there was no indication of an optimal value of L; consequently CCC which reduced L also reduced yield. D was closely related to the maximum quantity of nitrogen accumulated in the leaves per unit area of ground.

Effect of centre of production, maturity and storage treatment of seed tubers on the growth of early potatoes: II. Field growth

SUMMARYStudies were carried out on the effect of source, time of lifting and post-harvest treatment of apparently virus-free Arran Pilot seed potatoes on subsequent crop growth. The experiments were carried out in 1961–2 and 1962–3 at Efford, Sutton Bonington and Edinburgh. Seed tubers from the more southern region, which were older and showed greater sprout development at planting, gave plants with a higher stem number at soil level, a higher tuber number and a greater percentage of the tuber yield as seed grade than northern-produced seed. High bulking rates were associated with early emergence, high tuber numbers and late apparent time of tuber initiation. In 1962 southern seed produced plants which initiated tubers early and had low bulking rates and low final yields. In 1963 seed source had little effect on the time of tuber initiation of resulting plants, and southern-produced seed gave plants with high bulking rates and high final yields. Early lifted and greened tubers gave rise to plants with the same pattern of response as seed produced at the southern centre. It is suggested that this variation in response between years was due to the climatic conditions at the time of tuber initiation in the field crop.Seed of a required state at planting can usually be obtained by growth at the centre of ware production provided disease can be controlled and the time between harvesting of seed and planting is longer than about 3 months.

The effect of CCC and nitrogen on the growth and yield of the second early potato variety Craig's Royal

SUMMARYThe experiment described here is the second of a series of experiments investigating the effect of the time of application of certain plant nutrients on the growth of the potato crop. In this experiment all combinations of three rates of nitrogen (0, 0·75 and 1·50 cwts nitrogen per acre), two times of application (at planting and at the time of tuber initiation) and two rates of application of CCC (0 and 4 lb/acre applied twice, shortly after emergence) were tested and studied by the technique of growth analysis.There was a linear relationship between leaf area duration (D)and tuber dry matter yield, D accounting for 95 % of the variation in the latter. The maximum amount of nitrogen accumulated in the leaves (Nmax) was linearly related to D, and accounted for 86 % of the variation in D. This relationship was improved if separate regressions were calculated according to whether CCC had been applied or not. Calculated in this way, the regressions indicated that more nitrogen was required for a given value of D when plants were treated with CCC.Delaying the application of nitrogen resulted in a considerable improvement in the recovery of fertilizer nitrogen (ammonium nitrate). A heavy dressing of nitrogen at the time of planting did not enable the crop to take up sufficient nitrogen for maximum yield. Because of these factors, delaying the application of nitrogen significantly increased tuber yield at both rates of nitrogen tested.Increasing the rate of nitrogen and delaying its application tended to increase the proportion of stem in the total dry matter; CCC had the opposite tendency. CCC, however, reduced leaf area and the mean effect of CCC was to reduce tuber yields. While there wore no significant interactions between CCC and nitrogen treatments on final tuber yield, it was observed that CCC slightly increased yield when the highest rate of nitrogen was applied late. Ways are suggested in which CCC may be more effectively used.

Studies in potato agronomy. I. The effects of variety, seed size and spacing on growth, development and yield

1. Growth and development in relation to yield were studied in the two maincrop varieties King Edward and Majestic in 1959 and 1960. The effects of seed size and spacing were also investigated.2. The total tuber yield, and more particularly the ware yield, of Majestic was greater in both years. This was associated with a longer period of tuber bulking in this variety, due, in 1959, to earlier tuber initiation, and in 1960, to earlier tuber initiation and greater persistence of tuber bulking. Large seed outyielded small seed, although the difference, particularly in ware yield, was relatively small. The seed size effect was associated with a difference in the length of the bulking period, in consequence of a difference in the time of tuber initiation. Total yield tended to increase with decrease in spacing distance; ware yield increased as spacing distance decreased from 24 to 18 in., but there was little difference between 12 and 18 in. spacing. In general, low seed rates performed better than might be expected.