For the purpose of raising the level of selection efficiency in sugarcane breeding, it is necessary to establish selection criteria which can be eliminated reasonably a mass of the first stage seedlings. Standard characters for selection are to be chosen from practical ones which have higher heritability and correlation between each stages.
It is the purpose of this study to investigate a relationship of some practical characters between the first seedling stage and the successive clonal stages of sugarcane raised at Tanegashima Isle, South Western region of Japan, the results bling summerized as follows.
1) Correlation coefficients for stalk length, stalk biameter and pithiness ratio were all highly positive and significant, r values ranging from 0.5 to 0.7. Elimination in the early stages of evaluation would have been highly effective based on these three characters.
2) Numbers of millable stalk and weight per stool were highly correlated under the condition diminishing competition among seedlings in planting distance 85×85 cm. It is expected that productivity of seedling stage is reliable in such condition, whereas correlations for number of millable stalk were reduced by about r=0.3 as planting density increased in seedling population.
3) Correlation coefficients for Brix between the same clones in 1967, 68 were all positive ranging from 0.2 to 0.6. Frequency distribution of Brix used 299 clones is shown in Fig.1. It is evident that selection for Brix based on single stool would have been as effective in obtaining clones with high Brix and eliminating those with low Brix.
4) It may be possible to examine the period for suitable and early selection.

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The study was carried out in during period the 1969-70, at the Tanegashima Branch, Kyushu Agricultural Experiment Station. (N 30°40', E 131°), empolying the 46 selected lines the 4th stage bred from 8, 210 initial seedlings, involving 2 varieties of sugarcane, N: Co. 310 and 376, The investigations were conducted with following four sections involved respectively five characters.
(1) Yield components (2) Stalk form
(3) Juice quality (4) Leaf form
From the results of correlation coefficients computed between each others, an ideal varieties with higher sucrose content and yielding ability in sub-tropical districts were considered standing for “stalk number” and “stalk weight” type.
1) Correlation coefficients between the characters are summerized in Table 1. Figure 1 shows the correlation centering around yield of available sugar at above 5% significant level.
2) Correlations for yield of cane are higher with numbers of stalk (r=0.62) than with stalk weight (r=0.56) . It is discussed the reasons why yield of “stalk number” type are predominant over “stalk weight” type as the latitude elevates.
3) It is observed that Brix, sucrose per cent and available sugar ratio of “stalk number” type are higher than that of “stalk weight” type. Considering the relation from a standpoint of leaf habit, “stalk number” type is inclined to have narrow, short and erect leaf blade, which is desirable to perform effective photosynthesis in higher latitudinal districts at low incident angle of sunlight. On the other hand, “stalk weight” type is apt to have wide, long and drooping leaf blade, which gives an unfavourable effects on photosynthesis due to shade the lower leaves and to weaken the light intensity within the community tended to be disadvantageous for maturity.
4) The ideal varieties adapted in higher latitudinal districts are represented by the “stalk number” type exhibited higher yield and sucrose content, whereas the “stalk weight” type shows thick, heavy stalk which may give the illusion of higher yielding potential than the variety possesses.
5) Since sugarcane has the highest light-saturation point, the varieties cultivated under condition of rather lower enersy of sunlight in sub-tropical districts should possess reasonable plant type for efficient light acceptance.

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The root systems of one years-four years' pepper plants were observed in Belém, Amazonia region, in 1966-'67, and some problems in the cultivation under existing method on the stand point of this root system were considered:
Feature of root system.
1. The root system is derived from adventious roots which sprouted on the nodes of stem cutting.
2. The root system is divided into two groups in function on the bases of morphological appearance and position of rhizosphere namely;
a. nutrient absorbing root system.
b. water absorbing root system.
The former, consists of many roots, looks as slender in general, has many branches and finer roots, shallow rooted and spreads the longer horizontally and the more in the upper part of soil, e.g. 2years' and 4years' plants occupy 90% and 85% of total roots upto 30 cm depth, 98% and 90% up to 40cm depth respectively. The latter, consists of several roots, comparatively thick, elastic, waving sometimes twist, deep rooted, e.g. 4 years' plant reaches to 4m depth.
3. Develops well in aerial condition especially in the planting and fertilizing holes.
4. New roots of the nutrient absorbing root system are observed to develop in the end of the dry season already that is shortly after harvest.
5. Distribution of nutrient absorbing root system is uneven in radial and vertical directions.
6. Top-root ratio increases as the plant age increases.
Problems in the cultivation under existing method.
1. Drainage; drain off surplus water and to keep safe from water standing in the planting and fertilizing holes.
2. Mulching; recommend overall mulching with straw, haulm or other grasses.
3. Fertilizing; a) apply fertilizer by ring belt ditch method spreading out as the plant grows, in place of the existing single cubic hole. b) straw, haulm and compost are effective.
4. Fertilizing time is recommendable in the end of dry season and in the end of rainy season.
5. 30-40cm depth of digging to make planting and fertilizing holes under existing method is sufficient for root development.
6. The cultivating method, depending on mulching as a main point, combining with top dressing of fertilizer, disregarding hole making for fertilizer application is considered to be effective and is now under experiment.

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