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Results and Discussion
Chemical analysis of plant samples of all the genotypes for
mineral uptake efticiency and distribution at various
ontogenetic stages of Triticum aestivum L. is
depicted in Tables 2 to 4.
Mutant-37 of Indus-66 displayed significantly (P>=.01)
higher uptake of N than all the other genotypes at all
sampling dates in both sets of experiments. The N uptake of
M-38 of C-591 was significantly higher than its mother
cultivar at all sampling dates. In most of the cases Nayab
mutants have higher N uptake than their parent and Mexi-
Pak. However, Nayab mutant-27 was characterized by low grain
N and high straw N content (LARIK et al 1984b). This
observation indicate that this particular mutant is unable
to transfer the absorbed N from shoot to the grain. This
physiological function is undoubtedly gene controlled and
differences are therefore inherited and gene probably
determine not the character of complex, but the total uptake
of an element in any specific environment (SINGH & LAMB
1970). Similarly, most of the Indus mutants were higher in N
uptake than their parents and Mexi -Pak (Tables
2 to 4). M-27 was consistently higher than parent and
Mexi-Pak at all sampling dates. The differential uptake of
this mutant suggest that it has a greater uptake efficiency
as a result of either a stronger root system or greater
suction pressure. This probably accounts for the greater
nitrogen absorption of this mutant. On the contrary, low N
content of M-13 of Indus-66 in field experiment and M-28 and
38 of C-591 in pot experiment at maturity indicate the rapid
translocation of N to aerial parts. Similar varietal
differences in N uptake and utilization have been reported
by a number of workers (MCNEAL et al 1966 ; GASSER
& IORDANOV 1967 ; BRAUN & FISCHBECK 1976).
Mutants with superior P uptake and accumulation were also
identified in the present work (Tables
2 to 4). All mutants of Indus-66 had significantly
(P>=.01) higher uptake and accumulation of P at all
sampling dates than their parent and commercial variety
Mexi-Pak. M-38 of C-591 displayed higher P uptake than its
mother cultivar at all sampling dates except at second
harvest and at maturity in pot condition. Therefore, these
mutants can be classified as P-efiicient mutants as
suggested by BROWN (1966), because of their high P uptake
capabilities from the growing media. On the other hand,
Nayab mutants showed differential response to P uptake.
These studies clearly suggest genetic control of P
accumulation differences (BARBER et al 1967 ; LYNESS
1936 ; SAGGAR et al 1974).
The behaviour of the genotypes for K uptake and accumulation
is presented in Tables 2 to 4.
Generally the mutant genotypes have displayed improvement in
K uptake at different sampling dates under both sets of
conditions. Mutant-38 consistently exhibited higher K uptake
compared to its mother cultivar at various ontogenetic
stages under both conditions. Nayab mutants had
significantly higher K uptake than their parent. The
behaviour of M-37 of Indus-66 was not consistent. However,
this mutant showed significant deviations than the parent
and Mexi-Pak in K uptake potentialities. These results
further points to the genotypic differences in K uptake and
accumulation as well (CACCO et al 1976 ; GORSLINE
et al 1961 ; KLEESE et al 1968, WALKER &
SCHILLINGER 1975). These authors suggested that there are
wide varietal differences in such genetically determined
properties as ion transport and utilization.
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