Shoot apical meristem culture of maize, wheat, barley and oat --V. R. Bommineni and D. B. Walden We have reported the successful recovery of plantlets from 14 days-after-pollination (DAP) immature and 72 h imbibed shoot apical meristems of maize (Bommineni et al., MNL 63:87-88; Plant Cell Tissue Organ Cult., 1989, in press). No limitations were observed (such as genotype specificity, recovery of fertile plants, etc.), with this culture procedure. However, the explanted meristems were treated with different stress-related conditions (physical or horticultural) and the percentage of recovery of plantlets compared to our earlier data.

A summary of the data is in Table 1. Among the genotypes tested, the percentage of plantlets recovered is lower

Table 1: Recovery of maize plantlets through shoot apical meristems exposed to environmental stress conditions in field and glasshouse nurseries.
 
Genotype
Number
Percentage
 
Meristems
Plantlets
Plantlets
Plantlets
To maturity
 
Explanted
to nursery
to maturity
(3/2)
(4/3)
 
(2)
(3)
(4)
    
Field:          
wx wx
347
97
94
28
97
Oh43
155
49
45
31
92
A188
183
65
49
35
75
Total
685
211
188
31
90
           
Glasshouse:          
wx wx
876
386
361
44
94
A188X W23
20
10
10
50
100
Total
896
396
371
44
94

than that in our previous data. Further, there is a decrease in plantlet recovery in the field nursery compared to the glasshouse nursery. For example, in waxy (wx wx) genotype, 28% of plantlets were recovered in the field nursery in comparison to 44% in the glasshouse nursery. Once the plantlets became established, there was no further loss of plants either in the field or glasshouse (Table 1). The data on percentage of plantlets grown to maturity (column 6 in Table 1) is similar to the recovery of plantlets in our earlier reports.

Other cereal shoot apical meristem culture: We also attempted to apply basic culture protocol (without any treatment) to immature shoot apical meristems of wheat, barley and oat.

Immature seeds of wheat, barley, and oat were collected from the field in the summer of 1989. The grains were surface sterilized in 10% 'Javex' for 30 min after removing the glumes. Other procedures, dissections, and medium composition were similar to maize (MNL 63:87-88) and the final size of these meristems ranged from 0.5-0.8 mm. After 3 weeks of culture, the plantlets with roots and leaves were transferred to small plastic nursery pots (2-3 plantlets per pot) in the glasshouse and grown in the same pot through flowering.

Table 2. Recovery of plantlets through shoot apical meristem culture from immature embryos of wheat, barley and oat.
 
 
Number
Percentage
Crop (cultivar)
Meristems
Plantlets
Plantlets
Plantlets
To maturity
 
Explanted
to nursery
to maturity
(3/2)
(4/3)
 
(2)
(3)
(4)
    
Wheat (Agusta)
130
94
87
72
93
Barley (Birka)
142
80
75
56
94
Oat (Donald)
124
103
95
83
92

A high percentage of plantlets were recovered in all three cereals (Table 2). However, a maximum percentage of plantlets were recovered in oat (83%) and a lower percentage of plantlets were recovered in barley (56%). Fertile seeds were recovered from all the plants which flowered.

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors

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