Maincrop Varieties Research Articles

The effect of variation in the storage temperature of seed potatoes on sprout growth and subsequent yield

SUMMARYExperiments, conducted over 3 years, investigated the effect of all combinations of two storage periods at low temperature (0 or 2 °C) and two storage periods at 10 °C on the sprout growth, numbers of stems per tuber, foliage development and subsequent tuber yield of the two maincrop varieties Maris Piper and Désirée.Although the number of day-degrees accumulated during sprouting was the same for all treatment combinations, there were large effects of treatments on the number of sproutlets per tuber and the total sprout length per tuber. However, there was no effect on the number of stems per tuber, foliage development or saleable ware yield inany year.

Effects of tuber size on dry-matter content of tubers during growth of two maincrop potato varieties

Two experiments are reported which examined the relationship between tuber size and dry-matter content during growth of the maincrop varieties, Desiree and Maris Piper. The relationship was negatively quadratic throughout growth in both varieties but the decline in dry-matter contents at large tuber sizes was more marked in Maris Piper than Desiree. Dry-matter content of individual tuber sizes increased during the early stages of their growth but later declined: the magnitude of these changes was large. The implications of these effects of tuber size and time of harvest are discussed in relation to the determination of accurate dry-matter contents of treatments and varieties.

Effects of date of planting on growth and yield of contrasting potato varieties in Pembrokeshire

SummaryFour experiments over 2 years which examined the effects of date of planting (from mid-March to early May) on the growth and yield of early, second early and maincrop potato varieties are described. In two experiments the seed used was physiologically old (heavily sprouted) and in the other two experiments relatively young seed (limited sprout development) was used. In the early variety, Home Guard, tuber yield at maturity was unaffected by delay in planting when physiologically old seed was used but increased leaf area and higher tuber yields resulted from later planting of younger seed. With both types of seed the maincrop varieties, Desirée and Maria Piper, produced larger leaf areas from later planting in one year but smaller leaf areas in the other year. In both years with both types of seed, tuber yields at the end of August were higher from the earlier plantings of these varieties. The physiologically young seed of Red Craig's Royal behaved in a similar manner to the maincrop varieties and the physiologically old seed behaved in a similar way to Home Guard.Any yield advantages of early varieties over maincrop varieties from any date of planting were small and short-lived and the physiological reasons for differences between varieties are discussed in the light of these results. It is suggested that the current classification of varieties is unjustified and that variety testing should take more account of the effects of physiological age.Tuber yields from the maincrop varieties were very high (60·80 t/ha) and this is attributed to the synchrony of leaf growth and increasing light receipts which may be readily achieved in the mild springs of W. Wales.

Factors affecting potato production in France since 1950

In France potatoes account for only a small share of both farm output and the consumer's budget. * However, the prices of this staple food fluctuate widely, and detailed economic analysis of this behaviour is called for. The object of the study is to identify the economic factors explaining variations in the crop areas of the four kinds of potato grown in France - namely seed, early, main-crop and starch potatoes. The effects on crop areas of input and substitute prices are estimated as well as substitution effects between the four kinds of potato. As might be expected the price elasticities of supply are low. The long-run estimates are higher for seed and starch potatoes than for early and main-crop varieties. Production of the latter two is of a more speculative character than the former which are more dependent on structural conditions.

Belleisle1: A new maincrop variety with excellent table quality and bruise resistance

Belleisle is a maincrop variety with good yield, exceptional table and handling quality. It has some resistance to common scab, late blight andFusarium sambucinum.

Some effects of seed size and spacing on the yield and grading of two maincrop potato varieties: I. Final yield and its relationship to plant population

SUMMARYTwo experiments, which investigated the effect of three seed sizes and three withinrow spacings on the graded yield of the two early maincrop varieties Pentland Crown and Maris Piper, are described and the results discussed.Relationships were established between yields in various grades and stem population, and are used to explain the response of yield to changes in seed size and spacing. Comparisons between any two levels of the same treatment were affected by the size grade in which they were made. In addition, the tendency towards interactions between variety and seed size and between variety and spacing suggests that comparisons between varieties are affected by the populations at which these comparisons are made.

The reliability of a laboratory test for assessing gangrene susceptibility

The reliability of a laboratory test for determining varietal susceptibility to gangrene was assessed in two years. In both years ranking order of control varieties reflected their respective agricultural performances. There were highly significant correlations for varietal scores in tests carried out in the same year and at least for maincrop varieties, in tests carried out in different years. There were, however, significant variety × test interactions.

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.

Sable, a new early variety of potato

Sable is an early sizing potato variety of midseason maturity. It is comparable with the variety Warba in yield of marketable tubers 80 to 90 days after planting. It has white, smooth, bright, attractive tubers with shallow eyes, and is moderately resistant to common scab. It is not recommended as a main crop variety. It is low in dry matter; however, it cooks satisfactorily as an early variety.

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.

Relationships between set characters and yield in maincrop potatoes

1. Data are presented indicating that both the total yield of potatoes and the proportions of the yield in size grades were a function (independent of set size) of the number of main stems per unit area for the maincrop varieties Majestic and King Edward.

Potato haulm resistance to Phytophthora infestans

SUMMARYHaulm susceptibility to Phytophthora infestans (Mont.) de Bary of fourteen widely differing potato varieties was compared in laboratory and field tests with the maincrop variety Majestic as a standard. These two tests gave similar results except that the early varieties Viola and Arran Pilot were more resistant in the laboratory than in the field.The sequence of infection within the crop canopy was the same in susceptible and resistant varieties, starting first mainly on the lowest leaves on the stem, then the middle and finally the uppermost. This sequence was lost when haulm became prostrate. Varieties differed in the rate that infection spread and leaves were destroyed, some being attacked more rapidly, and others more slowly, than Majestic.In the field the fungus spored on different varieties as in the laboratory test; the annulus was wide and sporulation intense on susceptible varieties, but narrow and sparse on resistant ones.

THE VEGETATIVE DEVELOPMENT OF THE POTATO PLANT

A study of the vegetative growth of potato plants indicated that all varieties grown under identical conditions are likely to show similar growth rates during the early stages of development.Differences in total leaf area per plant between varieties became apparent at the stage when rapid development of axillary shoots from the main axis occurred. The maincrop varieties, Stormont Dawn and King Edward, attained a greater total leaf area than the early varieties, Ulster Chieftain and Arran Pilot, because of the greater development of axillary shoots.It is suggested that the number of nodes produced beneath the terminal inflorescence on the main axis approximates to a constant value, independent of variety. Varietal differences were manifested in the distribution between leaves above ground and stolons below, the early varieties producing fewer leaves above ground than the maincrop, in inverse proportion to the number of underground stolons.The yields of tubers per plant are given for four varieties. Differences between varieties in the rate of tuber formation are related to differences in the development of haulms.It is considered probable that the potato plant exhibits a basic growth form which is modified in each variety in a characteristic manner according to the stage in the growth cycle and the rate at which the growth substances are distributed to the various organs of the plant.

Chemical Prevention of Potato Dry Rot Disease

As a result of research during the past five years, Bayer Products, Ltd., Crawley Research Station, Brighton Road, Crawley, Sussex, claim to have developed a highly efficient preparation for the prevention of dry rot of potato tubers caused by the fungus Fusarium coeruleum. This preparation, marketed under the trade name of ‘Fusarex', is based on 2,3,5,6 tetrachlornitrobenzene, a chemical first described in 1868 by Jungfleisb, who prepared it by treating tetrachlorbenzene with fuming nitric acid for some hours at near boiling point. ‘Fusarex' is most effective for the control of dry rot when applied to the tubers immediately on lifting, followed by a period of four to six weeks storage in a clamp. It has been found in trials that the preparation does not need to cover each potato completely so long as an even distribution through the mass of tubers is obtained. Thus a simple manual application can be employed, involving no expense in labour or machinery, and no interference with the normal lifting operations. It has also been found that suitable ‘Fusarex' treatment and storage conditions can delay the development of sprouts by the tubers. The treatment of main-crop varieties to prevent sprouting is now a practical proposition ; but special techniques are still being worked out for early varieties. Intensive pharmacological tests have shown that tetrachlornitrobenzene is of such a low order of toxicity that it can be regarded as non-poisonous under the conditions of use suggested, and it is therefore safe to use on potatoes destined for human consumption and stock feeding.

Black scurf and stem canker of potato (Corticium Solani Bourd. & Galz.): Further field studies on the use of clean and contaminated seed potatoes and on the contamination of crop tubers

Black scurf and stem canker of the potato were investigated in field trials in contaminated soil at Warburton, Cheshire, to determine the effect of planting clean and contaminated seed (vars. Arran Banner and Majestic) on crop yield and on the contamination of the crop tubers.Black‐scurf contamination was prevalent on crops grown from clean seed and was not significantly different from that occurring on plots planted with contaminated seed. It was severe on early‐dug tubers, but was more severe on late‐dug tubers. Produce grown with and without stable manure was heavily contaminated.Contaminated seed caused a check to tuber formation and an appreciable increase in stem canker and in the number of primary shoots killed. Nevertheless, the yields from the manured, contaminated seed plots were satisfactory and were not lower than those from the clean‐seed plots. There was no relation between the yield and the amount of black scurf on the produce.The results of a trial made in a field which had been in grass for at least 43 years, suggested that the soil contained little, if any, Corticium Solani. Heavy contamination occurred on tubers grown under relatively dry soil conditions.In all the trials misses and wilted shoots caused by Corticium were rare and there was no premature yellowing or death of the haulms on the clean or contaminated seed plots.The evidence obtained in the four seasons from 1941 to 1944 indicates that in this country satisfactory yields of early maincrop and maincrop varieties may be obtained despite the prevalence of C. Solani in the soil and on the seed, provided the soil and cultural conditions are reasonably good.

Identification of Heterodera Species by Larval Length. Technique for Estimating the Constants determining the Length Variations Within a given Species

A complete investigation of the variations likely to occur in the lengths of larvae of Heterodera rostochiensis (for example) under all conditions would involve measuring larvae from a great number of varieties of potato grown in a great number of different localities, and also of larvae from tomatoes of different varieties grown under various conditions. The results obtained so far for this species of Heterodera make but a small contribution towards the mass of information which might be accumulated. Until such further data become available, certain conclusions have been drawn as to the best method of taking samples of larvae for measurement, but it must be remembered that these conclusions may need revision at a later date in the light of new information. According to our present knowledge it appears that the variety of potato on which a cyst has developed does not significantly affect the mean length of the larvae within, but that the mean length of the larvae from a single plant, irrespective of the variety, may differ significantly from that of larvae from another plant. It is also deduced that the variations in the mean lengths of the larvae from different cysts are greater than the variations within the individual cysts. From these facts it follows that if one wishes to estimate parameters for larval lengths of a population of H. rostochiensis larvae, a better estimate will be obtained if one takes a small number of larvae from each of a large number of cysts rather than the same total number of larvae from a small number of cysts. Similarly the cysts should have come from a large rather than a small number of plants, but apparently it is not necessary that the plants should be of as many varieties as possible, though this last assumption is based on information derived from only seven varieties of potato, all of them maincrop varieties, and it may need modification when larvae from other varieties have been examined.

A new potato variety from British Columbia

The results of the various trials and the observations gathered from different sources have shown that the Columbia Russet is one of the earliest of the main crop varieties and has considerable promise as a good yielder. It is worthy of trial on a wider scale, particularly on soils which are suited to varieties of the Green Mountain group. Under irrigation in British Columbia, it has not given very satisfactory results and the Netted Gem and Burbank varieties will undoubtedly remain the most popular under such conditions. Its cooking qualities are not considered so good as the Netted Gem when boiled but its keeping quality is considered equal to that of Netted Gem.

Hydrated Lime in Summer Sprays for the Control of the Oriental Fruit Moth

The results of laboratory tests and orchard spraying experiments conducted in Ohio during 1928 indicate that heavy applications of hydrated lime either alone or in combination with insecticides offer promise as a control for the Oriental Fruit Moth (Laspeyresia molesta Busck). Such sprays act as a physical and mechanical hindrance to oviposition, hatching and larval entry. In one orchard, the main crop variety, Elberta, was harvested with 91 per cent marketable and 85 per cent absolutely clean fruit, a reduction of 47 per cent in injured fruit and a decrease of 76 per cent in infestation in favor of the experimental treatment.