Report 31. Development of stock quality criteria

Abstract

This study examined survival and growth of seedlings of several species produced in standard and Deep 5 Rootrainers. The objectives were to test for differences between the two containers, and to determine the minimum size needed for outplanting. Instead of a random, representative sample, nursery seedlings having the smallest and largest root collar diameter were selected for outplanting. Root systems received a numerical root quality ranking as they were planted. Container effects were compared by analysis of variance (for morphological measurements) and by straight-line models (for patterns of growth). Occasional differences were discovered, but meaningful differences between standard and Deep 5 Rootrainers do not exist. Kasya demonstrated no container differences, but the five-cm initial height difference between neem trees growing in the two containers had not changed at nine months. Initial condition of the root system and root plug had little or no effect on subsequent field performance. Calculation of straight-line models showed only a very weak relationship between initial morphological measurements and field performance. However, grouping seedlings based on initial root collar diameter showed that those smaller than a species-dependent minimum performed poorly when outplanted. This critical minimum is not smaller than 2 mm, and may be larger. Seedlings smaller than this should not be allowed to leaving the nursery, and nursery practices which increase seedling root collar diameter must be encouraged.

Etid si-la examinin jan ti pyebwa differen espes chape le yo soti Woutrene fon ak pa fon. Objectif la sé pou testé pou diférens ki genyen ent dé (2) veso sa-yo. Objectif la sé tou détéminé gwosé ki pipiti ké nou bezwen pou planté en déyo de pépinyé-yo. Ti pyebwa nan pépinyé ki gen pi piti ak pi gwo diamet nan pié ti pyebwa-yo té choizi pou al planté an déyo pépinyé-yo. Pandan nou tap planté ti pyebwa-yo, nou te mete yon nimewo sou chak pyebwa, bou identifye kondisyon rasinn-yo. Efé veso-yo genyen sou ti pyebwa té komparé nan yon analiz de varians (pou mézi morfolojik) ak nan plizié modél ligne dwat (pou jan y-ap grandi). Nou té jwenn kék diférans pa si pa la. Diférans nou t'ap chéché-yo pa éksisté. Kasya pa bay ankenn diférans nan veso-yo, men ti diféranse nan oté de 5 cm ki genyen ent pié neem-yo k'ap grandi nan dé (2) veso-yo pa chanjé nan yon périod de 9 moi. Kondisyon première de sistém rasinn gen yon ti ou bien pa gen éfé sou péfomans nan jadin-yo. Kalkil sou modél ligne dwat démontré yon ti relasion ent mézi morfolojik ak péfomans nan jadin. Sepandan, ti pyebwa ki an group bazé sou gwosé diamét nan pié-yo démontré ti pyebwa ki pipiti pasé yon minimum de éspés pa bien remét lé yo planté nan jadin. Minimum kritik si-la pa pipiti ke 2.5 mm, et li ka pi laj. Ti pyebwa ki pipiti pasé si-la pat dwé kité pépinyé-yo. Fó yo sévi ak téknik ki agrandi diamét plis, nan pyebwa-yo.