IN VITRO CONSERVATION OF GROUNDNUT (ARACHIS HYPOGAEA L.).
IN VITRO CONSERVATION OF GROUNDNUT (ARACHIS HYPOGAEA L.).
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Date
2015-11
Authors
ABDULMALIK, Maimuna Mohammed
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Abstract
Experiments were carried out between 2009 and 2013 in the Biotechnology laboratory,
Department of Plant Science, Ahmadu Bello University Samaru, Zaria with the aim of
developing tissue culture regeneration, cryopreservation and slow growth protocols for
conservation of groundnut. Embryonic axes obtained from seeds of Four (4) groundnut
varieties; (SAMNUT 10, SAMNUT 21, SAMNUT 22 and SAMNUT 23) were used in the
study. In the regeneration experiment, results showed that maximum shoot multiplication was
obtained from Murashige and Skoog (MS) medium supplemented with 15 mg/L BAP.
Among the groundnut varieties evaluated SAMNUT 23 and SAMNUT 22 recorded the
maximum shoot height (4.7 and 4.8cm, respectively). For in vitro rooting, MS media
supplemented with 1 mg/L NAA produced the highest root-induction frequency (82%).
While the hormone free medium recorded the longest roots (7.4cm). A Significant genotypic
effect was also observed, with SAMNUT 22 having the highest root-induction frequency
(60%).
In the cryopreservation study, the desiccation technique gave the highest survival of 97% -
100% and shoot formation of between 92% and 97% of cryopreserved embryonic axes at an
average moisture content of 17% after 4 - 5 hr desiccation. Among the varieties evaluated,
SAMNUT 23 and SAMNUT 22 recorded the highest survival of 65% and shoot formation of
57-60% respectively. The results of the vitrification technique showed that the highest
survival (70%) and shoot formation (65%) were obtained from embryonic axes treated for 2
hr in PVS2. SAMNUT 22 and 23 gave the highest survival of 74% and 76% and shoot
formation of 72% and 73% after cryopreservation. A significant interaction was observ
etween the varieties and dehydration time in PVS2 on survival and shoot formation. Highest
shoot formation was observed in SAMNUT 10, SAMNUT 21 and SAMNUT 23 after 2 hr
dehydration in PVS2. In the case of SAMNUT 22 this was achieved after 3hr dehydration in
PVS2. In the encapsulation-dehydration, the highest survival of 73% and shoot formation of63% of encapsulated cryopreserved embryonic axes of groundnut was obtained after 6hr air
dehydration to moisture content of 20%. Among the varieties evaluated SAMNUT 23
recorded the highest survival of 67% and shoot formation of 61% respectively. In the
encapsulation-vitrification technique, maximum survival rate of cryopreserved encapsulated
embryonic axes was 48% obtained after 1hr dehydration in PVS2. Among the varieties
evaluated SAMNUT 22 and SAMNUT 23 produced the highest survival rates of 44% and
42% respectively. A Slow growth experiment was conducted with four conservation media
(MS medium+30g/L sucrose, MS medium+20 g/L sucrose +10 g/L mannitol, MS medium+15
g/L sucrose +15 g/L mannitol and MS medium+10 g/L sucrose +20 g/L mannitol) and for
four conservation periods (3, 6, 9 and 12 months). Results revealed that the highest survival
rate (34%) and lowest shoot height (3.03cm) were obtained on MS medium supplemented
with 10g/L sucrose and 20 g/L mannitol. Among the varieties evaluated SAMNUT 23
recorded the highest survival (33%). With regard to the effect of different conservation
periods, the highest survival (74%) was obtained from cultures conserved for 3 months.
This study indicates that MS medium supplemented with 15mg/L BAP and MS medium
supplemented with 1mg/L NAA is suitable for shoot multiplication and in vitro rooting of the
groundnut varieties respectively. The techniques of desiccation, vitrification and
encapsulation could be used for the cryopreservation of embryonic axes of groundnut. Also,
MS medium supplemented with 10g/L sucrose and 20g/L mannitol could be used for the
medium term conservation of groundnut with subculturing intervals of three (3) to six (6)
months.
Description
A THESIS SUBMITTED TO THE POST GRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
IN PARTIAL FULFILMENT FOR THE AWARD OF DOCTOR OF PHILOSOPHY
IN PLANT PHYSIOLOGY.
DEPARTMENT OF PLANT SCIENCE
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA.
Keywords
VITRO CONSERVATION,, GROUNDNUT,, (ARACHIS HYPOGAEA L.).,