Pollination of the bartlett pear

              NEIT MiDfiCO COLLMA OF AGruCULN'RJ AND T.IECHANIC ARTS
AND AGRJCTIITURAL S(PERruE}N STATIO}I
Press Bultetin I94
POLLIMTI0I'I OF THE B*trILEIT PEii\R
During recent years there have been a nu.uber of investigations conducted by dif-ferent
investigators throughout the corrntry on rtrat is ordinarily ealled the self-sterility
of varieties of dlfferent fnrits. The results seem to indicate that under
certain conditions sone of the rrarieties nay be self-sterlle; that is to say, they will
not set fruit with their own pollen. Anong those varieties which have been reported
as self-sterile by eastern investtgators is the Bartlett pear. Tltrile the self-sterilit;
of certain varieties is now recognized, at the sa.ne ti-me it is also knoyrn that self-sterility
of fnrits is not a pennanent f,eature, but that this characteristic is in-flueneed
}argely by local and seasonal condltions. It has been found that varieties
rvhich nay fail to set fnrit one season or ln one locality on account of selfsterility
nay fnrit the following year or rhen taken to another place.
Inquiries from some of the prospectlve pear growers in Ner Mexico are beirg re-eeived
by the Departnent of Horticulture regarriing the self-sterllity of the Bartlett
pear r.mder our conditions. For manJr years Bartlett pear trees have been grown up and
down the Rio Grande V alley, and as far as knorn there has never been a conplaint of
shortage of crop on these trees due to self-sterility. The natter has been taken up
wi-th some of the larger Bartlett pear growers 1n the Rio Grande VaILey, as well as in
the west. One of, the largest and most successful Bartlett pear growers in the IIio
Grande Valley salrs: rrl do not think the Bartlett pear reguires any pollinatj.on frorn
other varj-eties, from the fact that where there are trees of other varleties in ny
orchard I do not observe that the Bartlett trees in that vicinity have nore or better
fruit than where Bartlett trees are alone.rl
In looking further into this question, one of the best authorities on the subject
in the northwest has the following to say: trAfter working on this subject a series of
years in varj-ous parts of the northwestl we find that the problen, to a certain degree,
b eeornes ltore or less of a local one; that is, vlrieties that night be self-sterile in
the East night be thor.oughly self-fertlle here, and vice versa. As a rrrlee the Bartlet'
pear is not self-fertile; but with us it is self-fertile.
From these preliminary investigetions on the subJect of selfsteriJity of the
Bartlett pear under our vrestern conditions, it appe,:rs that the Bartlett does not show
very strong indic+tion of being self-sterile. Since self-sterility is not a permanent
character, but mry be influenced by local or seasoniil, conditions, it would be well to
consider this problem pretty thoroughly in the planting of Bartlett orchards. It is
now a weIL known fact that in cases where varieties do not set fmit with their own
pollen they can be fertilized vrith pollen of other varieties. Theref,ore, it is rec-onmended,
as a rule--paftlcutarly for eastenn condj.tions--that in planting orcherds
the varj-etles be nixed, in order to facilitate cross pollinetion. It is frequently
recomnended that every other row be planted of the different varieties. Such a systen
of planting, under our conditions, is not very desir:ble. Yet, in order to be on the
safe side and avoid any possibility of shortage of crop in our Bartlett orchards on
account of self-sterility, it is advis:ble that the planters uss sone other veriety
arnong their Bartlett trees. The orchard can be.planted in oblong blocksr ild every
tenth to fifteenth roir be planted of another variety to be used as a pollinizer. In
this irray the danger of a shortage of crop on account of self-sterilityr can be great-
Iy reduced. Some of the varieties that are r€coinmended for pollinizers are the
DrAjou and the lfi-nter Nelis. I'fhatever variety is used for this put?oser it mrst bloom
at the sa.me tiime th:rt the Bartlett does. In orchards which are alrea4y plantedr mJt
vacancies that are to be replaced could tre plarrted to some variety to be used as a
pollinizer; or one or two rows on the outside rnight be planted of other vsrieties.
T he chances are, however, that under our conditions, judglng from our preliminary
investigation, the Baytlett is not very llkely to be self-sterile. Tetr it is neIl
to be on the safe side and plant a few trces of anothen variety; the nurnber, of course,
depending upon the size of the orchard.
Fabian Garcia