Droë massaproduksie van vyf eenjarige Medicago‐genotipes in die sentrale oranje‐vrystaat, soos beinvloed deur planttyd

Uittreksel

Bogrondse droë massa‐opbrengste (DM) van Medicago truncatula, cvv. Cyprus en Jemalong, M. aculeata var. inermis, cv. SA 4438, M. orbicularis, cv. SA 2552 en M. rugosa, cv. Paragosa wat op ses verskillende datums gevestig is, is in ‘n veldproef onder besproeiing bepaal. Die plantdatums was c. 15 dae gespasieer, vanaf middel Februarie tot einde April, DM is op drie stadiums bepaal naamlik drie weke na opkoms, begin blomstadium en met die aanvang van peulverkleuring toe finale DM ongeveer bereik is. Uiteindelik is peul‐ en saadopbrengs ook bepaal.

Die DM op drie weke het in alle gevalle sterk afgeneem namate later geplant is en die temperature gedaal het, terwyl die opbrengs met blom en peulverkleuring grootliks bepaal is deur die tydsverloop vanaf plant tot die betrokke stadiums. Die gemiddelde finale DM oor die ses plantings was 11,5; 10,7; 8,4; 6,7 en 5,0 t/ha vir Jamalong, SA 4438, Cyprus, Paragosa en SA 2552 onderskeidelik. Die gemiddelde saadopbrengste het gewissel van 650 kg/ha by Paragosa tot 2460 kg by SA 2552.

Abstract

Above ground dry matter production (DM) of Medicago truncatula, cvv, Cyprus and Jemalong, M. aculeata var. inermis, cv. SA 4438, M. orbicularis, cv. SA 2552 and M. rugosa, cv. Paragosa, established on six different dates, was determined in an irrigated field trial. The planting date were spaced c. 15 days apart, from mid February until the end of April, DM was determined at three stages, namely three weeks after emergence, the beginning of flowering and the onset of pod colouring when the approximate peak DM was reached. Eventually pod and seed yields were also determined.

At three weeks a progressive reduction in DM was recorded with later planting, which was ascribed to the associated drop in temperature. The yields at flowering and pod colouring, on the other hand, were largely determined by the time lapse from establishment until the specific stages were reached. The mean peak DM production over the six plantings were 11,5; 10,7; 8,4; 6,7 and 5,0 t/ha for Jemalong, SA 4438, Cyprus, Paragosa and SA 2552 respectively. Mean seed yields varied from 650kg/ha in Paragosa to 2460 kg in SA 2552.

Additional index words:

• Medicago aculeata
• Medicago orbicularis
• Medicago rugosa
• Medicago truncatula: Seed production

Notes

Departement van Landbou, Privaatsak X180, Pretoria, 0001.